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8 pages, 3147 KB

Open AccessProceeding Paper

Evaluation of Isogrid Rib-Stiffened and Conventional Helicopter Fuselage Panels Under Discrete Damage and Complex Loading Scenarios

by Odeh Dababneh and Alex John Pullan

Eng. Proc. 2025, 119(1), 1; https://doi.org/10.3390/engproc2025119001 - 5 Dec 2025

Viewed by 239

Abstract

This study examines how circular and star-shaped damage affects Aluminum-2024-T3 helicopter fuselage panels, focusing on damage shape, size, and location. Using finite element analysis, conventional stiffened panels are compared with isogrid rib-stiffened ones under combined compression and shear. Isogrid panels show superior performance, [...] Read more.

This study examines how circular and star-shaped damage affects Aluminum-2024-T3 helicopter fuselage panels, focusing on damage shape, size, and location. Using finite element analysis, conventional stiffened panels are compared with isogrid rib-stiffened ones under combined compression and shear. Isogrid panels show superior performance, with reduced displacements, lower von-Mises stress, higher stiffness, and improved damage resistance, especially against star-shaped damage. They retain higher natural frequencies and stability under damage, while conventional panels lose performance, especially in mode one. Isogrid panels also achieve higher buckling load factors, maintaining structural integrity despite damage, making them ideal for design optimization despite a 16.7% weight increase. Full article

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9 pages, 1488 KB

Open AccessProceeding Paper

Calculation of Fatigue Lifetime of Mooring Line with Deterministic and Probabilistic Analysis Methods

by Nikolaos Mossialos and Dimitrios Konispoliatis

Eng. Proc. 2025, 119(1), 2; https://doi.org/10.3390/engproc2025119002 - 9 Dec 2025

Viewed by 218

Abstract

The majority of the fatigue damage on offshore structures is generally assumed to be caused by relatively frequently occurring moderate sea states, i.e., sea states with significant waves lower than 7 m. This study aims to investigate the interrelationship between fatigue damage versus [...] Read more.

The majority of the fatigue damage on offshore structures is generally assumed to be caused by relatively frequently occurring moderate sea states, i.e., sea states with significant waves lower than 7 m. This study aims to investigate the interrelationship between fatigue damage versus sea state severity on a moored offshore hybrid structure for wind and wave energy absorption. The analysis is performed using both a deterministic and a probabilistic method. The spectral-based fatigue assessment method is the deterministic element, and it attempts to account for the random nature of sea states in a rational manner. The analysis is performed using sea scatter diagrams and then developing the structure’s stress response spectrum. The probabilistic method uses the Rayleigh and lognormal cumulative density functions of the stresses in order to predict the probability of survival over a 31-year period, which is the period covered by the records. Full article

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8 pages, 1435 KB

Open AccessProceeding Paper

Estimation of the Size of a Growing Crack Through Strain Sensing Under Uncertainty

by Anastasia Valma, Nicholas Silionis and Konstantinos Anyfantis

Eng. Proc. 2025, 119(1), 3; https://doi.org/10.3390/engproc2025119003 - 9 Dec 2025

Viewed by 247

Abstract

Fatigue cracks in highly stressed regions of marine structures, caused primarily due to wave loading, are critical life-limiting factors that can lead to structural failure. Structural Health Monitoring (SHM) systems offer the ability to remotely monitor damage progression during its initial phases, enabling [...] Read more.

Fatigue cracks in highly stressed regions of marine structures, caused primarily due to wave loading, are critical life-limiting factors that can lead to structural failure. Structural Health Monitoring (SHM) systems offer the ability to remotely monitor damage progression during its initial phases, enabling failure prevention. One diagnostic approach utilizes the strain redistribution in the vicinity of the crack tip, captured by sensor readings, to inversely calculate the corresponding crack length. This work addresses the challenge of accurately calculating the crack length under variable sources of uncertainty by employing the statistical framework of Maximum Likelihood Estimation (MLE). The method is demonstrated on a simplified test geometry using simulated strain data, registered at locations where structural response sensors may be placed. This approach enables the integration of multiple strain features at modest computational cost, facilitating the assessment of different sensor placement strategies under realistic noise conditions. Full article

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7 pages, 742 KB

Open AccessProceeding Paper

Design and Construction of a 3D-Printed Strain Sensor for Monitoring Bending Strain

by Isidoros Iakovidis, Dimitrios Nikolaos Pagonis, Sofia Peppa and Nektaria Maria Nikolidaki

Eng. Proc. 2025, 119(1), 4; https://doi.org/10.3390/engproc2025119004 - 9 Dec 2025

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Abstract

Additive manufacturing offers several advantages, such as rapid prototyping, cost-efficient production, and flexibility in constructing components. This work presents the design and fabrication of a strain sensor capable of generating electrical signals under applied mechanical loads, enabling potential failure prediction. The sensor was [...] Read more.

Additive manufacturing offers several advantages, such as rapid prototyping, cost-efficient production, and flexibility in constructing components. This work presents the design and fabrication of a strain sensor capable of generating electrical signals under applied mechanical loads, enabling potential failure prediction. The sensor was manufactured using the Fused Deposition Modeling 3D-printing process, combining acrylonitrile-styrene-acrylate as structural and protective layers with a conductive polylactic acid matrix containing carbon nanotubes as the sensing element. To assess its performance, the sensor was embedded within a Glass Fiber-Reinforced Polyester composite and subjected to bending tests. The results demonstrate a reliable sensing response, characterized by a measurable increase in electrical resistance under bending load. Moreover, the change in resistance increased with applied bending force, demonstrating the sensor’s feasibility for structural health monitoring applications. Full article

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9 pages, 1285 KB

Open AccessProceeding Paper

Reliability of Strength Test Results on Materials Using Statistical and Computational Methods

by Alexander Savaidis, Stamatia Gavela and Georgios Papadakos

Eng. Proc. 2025, 119(1), 5; https://doi.org/10.3390/engproc2025119005 - 10 Dec 2025

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Abstract

Destructive testing evaluates material strength but prohibits repeated measurements on the same specimen. Finite element simulations, such as those using ANSYS Mechanical, provide a cost-effective alternative by delivering deterministic solutions under defined conditions. To incorporate input variability, the Monte Carlo method applies assigned [...] Read more.

Destructive testing evaluates material strength but prohibits repeated measurements on the same specimen. Finite element simulations, such as those using ANSYS Mechanical, provide a cost-effective alternative by delivering deterministic solutions under defined conditions. To incorporate input variability, the Monte Carlo method applies assigned probability distributions to parameters like magnitude and angle of the applied force and geometric tolerances of the specimen. Thus, input variability yields distributions for output such as stress and deformation, enabling uncertainty quantification. In this study, an example of static force on a concrete cube was modeled in ANSYS, and uncertainty was propagated using the Monte Carlo method, as described in JCGM 101:2008. This approach enables the identification of critical factors affecting the outcome and provides confidence intervals that might be used as decision rules to support comparisons of numerical simulations with experimental data and of results of different models and to calculate the limits of quality control charts of a testing laboratory. Full article

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8 pages, 2267 KB

Open AccessProceeding Paper

On the Deformation and Energy Absorption Under Tension and Compression of an Auxetic Structure Made by SLA Resin

by Anargyros Stratis, Ioannis Papantoniou and George-Christopher Vosniakos

Eng. Proc. 2025, 119(1), 6; https://doi.org/10.3390/engproc2025119006 - 10 Dec 2025

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Abstract

Auxetic structures exhibit a negative Poisson’s ratio, enabling enhanced energy absorption and deformation capabilities compared to conventional materials. In this study, a re-entrant auxetic geometry was fabricated using stereolithography (SLA) 3D printing with a high-toughness resin and was tested in tension and compression. [...] Read more.

Auxetic structures exhibit a negative Poisson’s ratio, enabling enhanced energy absorption and deformation capabilities compared to conventional materials. In this study, a re-entrant auxetic geometry was fabricated using stereolithography (SLA) 3D printing with a high-toughness resin and was tested in tension and compression. Two variants, i.e., a reference and a filleted design, were investigated through finite element analysis and experimental testing. Results showed good agreement between simulations and experiments. The filleted geometry demonstrated smoother deformation, delayed fracture, and higher strain capacity, while the reference absorbed slightly more energy in compression. These findings highlight the role of geometry in tailoring auxetic performance. Full article

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8 pages, 1392 KB

Open AccessProceeding Paper

NTSB Investigations of High-Strength Steel Landing Gear Components Fracturing from Fatigue by Excessive Grinding

by Erik M. Mueller, Michael Meadows, Pocholo Cruz and Michael Hauf

Eng. Proc. 2025, 119(1), 7; https://doi.org/10.3390/engproc2025119007 - 10 Dec 2025

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Abstract

The National Transportation Safety Board is an independent federal agency investigating transportation accidents across aircraft, rail, pipeline, marine, highway, and hazardous materials platforms. The agency has investigated multiple accidents involving fractures of landing gear components during touchdown, where the trunnion pins fractured from [...] Read more.

The National Transportation Safety Board is an independent federal agency investigating transportation accidents across aircraft, rail, pipeline, marine, highway, and hazardous materials platforms. The agency has investigated multiple accidents involving fractures of landing gear components during touchdown, where the trunnion pins fractured from fatigue. Detailed analysis revealed that the crack initiation sites coincided with areas displaying marks consistent with excessive heating. These marks, or ‘burns’, developed during grinding operations from rework of the parts. The investigation details how fatigue cracks initiate from excessive grinding, the fracture morphologies observed, and the diagnosis of the issue in an investigation. Safety improvements were developed to prevent the fracture from recurring, noting the challenges of finding areas of excessive grinding on high-strength steel parts during rehabilitation. Full article

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8 pages, 1005 KB

Open AccessProceeding Paper

An Advanced Stochastic 1D Inverse Finite Element Method for Strain Extrapolation with Experimental Validation

by Jacopo Bardiani, Roberto Marotta, Emanuele Petriconi, Georgios Aravanis, Andrea Manes and Claudio Sbarufatti

Eng. Proc. 2025, 119(1), 8; https://doi.org/10.3390/engproc2025119008 - 10 Dec 2025

Viewed by 304

Abstract

The Inverse Finite Element Method (iFEM) is a valuable tool for reconstructing displacement fields from strain measurements, making it ideal for structural health monitoring. Traditional iFEM approaches are deterministic and typically require dense sensor networks for accurate results. However, practical constraints—such as limited [...] Read more.

The Inverse Finite Element Method (iFEM) is a valuable tool for reconstructing displacement fields from strain measurements, making it ideal for structural health monitoring. Traditional iFEM approaches are deterministic and typically require dense sensor networks for accurate results. However, practical constraints—such as limited sensor placement and cost—call for robust extrapolation techniques to estimate strain in non-instrumented regions. This paper proposes a stochastic 1D iFEM framework that integrates uncertainty quantification into the strain extrapolation process. By assigning confidence weights to extrapolated values, the method enhances the reliability of displacement reconstruction in sparsely instrumented structures. The approach is validated through numerical and experimental studies, demonstrating improved accuracy and robustness compared to traditional interpolation methods, even under varying loading conditions. The results confirm the method’s suitability for real-world applications in aerospace, civil, and naval engineering, particularly when direct strain measurements are limited. Full article

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9 pages, 12079 KB

Open AccessProceeding Paper

Microstructural Study of Welded and Repair Welded Dissimilar Creep-Resistant Steels Using Different Filler Materials

by Stavros Chionopoulos, Aimilianos Zervas and Michail Mathioudakis

Eng. Proc. 2025, 119(1), 9; https://doi.org/10.3390/engproc2025119009 - 11 Dec 2025

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Abstract

This study examines initial and repair welds between creep-resistant steels, P22 and P91, using ER90S-B3 and ERNiCrMo-3 steel-based and nickel-based filler materials, respectively. TIG welding with and without PWHT was applied. Microstructural evaluation revealed martensitic transformation in HAZ, decarburization in repairs, and the [...] Read more.

This study examines initial and repair welds between creep-resistant steels, P22 and P91, using ER90S-B3 and ERNiCrMo-3 steel-based and nickel-based filler materials, respectively. TIG welding with and without PWHT was applied. Microstructural evaluation revealed martensitic transformation in HAZ, decarburization in repairs, and the presence of Laves phase. Ni-based filler welds showed greater inhomogeneity. Hardness profiles confirmed softening in P91 HAZ and improved uniformity with PWHT. Steel-based filler provided better compatibility, especially in repair scenarios. The results support the use of ER90S-B3 with PWHT for enhanced reliability. Our findings align with EPRI guidelines and standards for weld integrity in high-temperature piping applications. Full article

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8 pages, 1268 KB

Open AccessProceeding Paper

On the Structural Integrity of Seam Welds in Cylindrical Pressure Vessels

by Paschalis Adamidis, Christos Gakias, Efstratios Giannakis and Georgios Savaidis

Eng. Proc. 2025, 119(1), 10; https://doi.org/10.3390/engproc2025119010 - 11 Dec 2025

Viewed by 642

Abstract

Pressure vessels are widely used in domestic and industrial applications. Despite their extensive usage, the fatigue behavior of their seam welds, which are inherent stress concentrators, is not addressed within a well-established methodological framework, especially under real operating conditions. This study proposes a [...] Read more.

Pressure vessels are widely used in domestic and industrial applications. Despite their extensive usage, the fatigue behavior of their seam welds, which are inherent stress concentrators, is not addressed within a well-established methodological framework, especially under real operating conditions. This study proposes a fatigue-based structural integrity assessment methodology for a seam weld in a cylindrical pressure vessel. Using both the Nominal Stress Method and the Effective Notch Stress Method, the weld was evaluated under realistic pressure loads. Results demonstrate that while both approaches suggest a very high fatigue life under assessed conditions, the Effective Notch Stress Method provides a more refined, less conservative estimate, particularly valuable for thin-walled configurations. Full article

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8 pages, 3205 KB

Open AccessProceeding Paper

A New Testing Procedure to Quantify and Assess Fatigue Properties of High-Performance Leaf Springs

by Efstratios Giannakis, Paschalis Adamidis, Christos Gakias and Georgios Savaidis

Eng. Proc. 2025, 119(1), 11; https://doi.org/10.3390/engproc2025119011 - 11 Dec 2025

Viewed by 368

Abstract

This paper focuses on the study of the material and component fatigue parameters of high-performance leaf springs used in the suspension systems of heavy-duty commercial trucks. Currently, there is limited information on the fatigue performance, material characteristics and surface properties of leaf spring [...] Read more.

This paper focuses on the study of the material and component fatigue parameters of high-performance leaf springs used in the suspension systems of heavy-duty commercial trucks. Currently, there is limited information on the fatigue performance, material characteristics and surface properties of leaf spring components, as manufacturers do not disclose this data. Therefore, production engineers need to conduct extensive experimental testing throughout various phases of product development, consuming significant resources and time. The paper presents well documented experimental procedures on a big variety of testing samples and prototypes with a set methodology providing valuable data such as (a) understanding of the advanced mechanical properties of new leaf-spring production lines, (b) settlement of a well-founded basis for the development of new theoretical tools, and (c) reducing the existing development and testing effort. Full article

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8 pages, 4348 KB

Open AccessProceeding Paper

Effect of Artificial Ageing on Mechanical Properties of Recycled Polypropylene Hollow Chamber Sheets

by Stamatina Theochari, Agathi Anthoula Kaminari, Angelos Kaldellis, Athanasios Karabotsos, Isidoros Iakovidis, Stavros Chionopoulos, Theano Vlachou and Athina Georgia Alexopoulou

Eng. Proc. 2025, 119(1), 12; https://doi.org/10.3390/engproc2025119012 - 11 Dec 2025

Viewed by 363

Abstract

Packaging materials made from polypropylene (PP) can be used to protect cultural heritage objects from damage ensuring their long-life preservation. This research work concerns the assessment of recycled polypropylene hollow chamber sheets as potential packaging materials for archival collections and cultural heritage objects. [...] Read more.

Packaging materials made from polypropylene (PP) can be used to protect cultural heritage objects from damage ensuring their long-life preservation. This research work concerns the assessment of recycled polypropylene hollow chamber sheets as potential packaging materials for archival collections and cultural heritage objects. It was carried out through a multidisciplinary diagnostic methodology combining mechanical methods, non-destructive imaging techniques in visible light (VIS), and ultraviolet-induced visible luminescence (UVL), as well as handheld digital microscopy, colorimetry, glossimetry, and SEM microanalysis. The results showed that the condition and mechanical performance of the specimens are affected by the ageing process. Full article

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9 pages, 4136 KB

Open AccessProceeding Paper

Analysis of the Failure of the Rotating Support Girder of a Spreader Bridge

by Przemysław Moczko, Maciej Olejnik and Jędrzej Więckowski

Eng. Proc. 2025, 119(1), 13; https://doi.org/10.3390/engproc2025119013 - 11 Dec 2025

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Abstract

This paper describes an example of a failure of the rotating support girder of a spreader bridge. The root cause of the damage was buckling of one of the girder’s plates. This caused plastic deformation, which made the continued safe operation of the [...] Read more.

This paper describes an example of a failure of the rotating support girder of a spreader bridge. The root cause of the damage was buckling of one of the girder’s plates. This caused plastic deformation, which made the continued safe operation of the machine impossible. An FEM analysis was performed to determine the probable cause of the failure. Conclusions and recommendations are also presented in the paper to prevent similar failures in the future. Full article

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8 pages, 1675 KB

Open AccessProceeding Paper

Assessing the Ageing Effect of Green Organic Coatings Under-Development on Bronze Alloy Substrate

by Angelos Kaldellis, Agathi Anthoula Kaminari, Stamatina Theochari, Athanasios Karabotsos and Athina Georgia Alexopoulou

Eng. Proc. 2025, 119(1), 14; https://doi.org/10.3390/engproc2025119014 - 12 Dec 2025

Viewed by 190

Abstract

Green organic coatings are developed to be deposited on and protect metallic cultural heritage artefacts from environmental degradation. This research work is carried out through a comparative study of under-development green organic and commercial coatings for indoor and outdoor applications against an artificial [...] Read more.

Green organic coatings are developed to be deposited on and protect metallic cultural heritage artefacts from environmental degradation. This research work is carried out through a comparative study of under-development green organic and commercial coatings for indoor and outdoor applications against an artificial ageing environment. Non-destructive techniques, such as Colorimetry, Glossimetry, Eddy-current thickness measurements, and SEM-EDS investigation, are employed to assess the studied bronze substrate-coating mock-up systems’ behavior. The results showed some correlations among the studied parameters, such as the thickness–colour (namely ΔΕ parameter) relationship, while comparative conclusions provide consultant suggestions for cultural heritage conservation applications. Full article

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9 pages, 1157 KB

Open AccessProceeding Paper

Reduction in the Estimation Error in Load Inversion Problems: Application to an Aerostructure

by George Panou, Sotiris G. Panagiotopoulos and Konstantinos Anyfantis

Eng. Proc. 2025, 119(1), 15; https://doi.org/10.3390/engproc2025119015 - 15 Dec 2025

Viewed by 215

Abstract

The present work focuses on the inverse identification of loads acting on wing-like geometries, through strain measurements. These loads are considered quasi-static and considered acting at discrete stations across the span of the wing. A demonstrative case study is investigated, focusing on a [...] Read more.

The present work focuses on the inverse identification of loads acting on wing-like geometries, through strain measurements. These loads are considered quasi-static and considered acting at discrete stations across the span of the wing. A demonstrative case study is investigated, focusing on a complex composite structure, an Unmanned Aerial Vehicle (UAV) fin. To achieve this, a high-fidelity Finite Element model is developed, with “virtual” strain data generated through simulations. The technical challenge of optimal sensor placement is addressed with D-optimal designs, which promise sensor networks (sensor locations and strain components) that produce minimal uncertainty propagation from strain measurements to load estimates. These designs are obtained through the implementation of Genetic Algorithms. Different sensor networks with an increasing number of sensors are evaluated in order to identify a further reduction in epistemic uncertainty posed by the problem’s ill-conditioned nature. Full article

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9 pages, 1525 KB

Open AccessProceeding Paper

Innovative Fatigue Design Approaches for Tension Springs Using the FKM-Guideline ”Analytic Strength Assessment for Springs”

by Christian Otto and Ulf Kletzin

Eng. Proc. 2025, 119(1), 16; https://doi.org/10.3390/engproc2025119016 - 12 Dec 2025

Viewed by 237

Abstract

The standard EN 13906-2 forms the essential basis for the design and calculation of helical tension springs. It is used not only nationally, but throughout Europe and internationally in the spring industry and by spring users. With regard to cyclic design, the standard [...] Read more.

The standard EN 13906-2 forms the essential basis for the design and calculation of helical tension springs. It is used not only nationally, but throughout Europe and internationally in the spring industry and by spring users. With regard to cyclic design, the standard only refers to fatigue tests to be carried out. There are no formulas for the analytical calculation of the existing stresses in the loops and no methods or diagrams for determining the permissible stresses for tension springs. Even in the technical literature, there are no reliable analytical formulas for calculating the existing stresses for extension springs with different loop shapes. This article presents solutions for determining existing stresses using numerical calculations, which are necessary for performing fatigue strength analysis for tension springs. Full article

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8 pages, 2269 KB

Open AccessProceeding Paper

Tensile Behavior of Romanian ‘Țurcana’ Sheep Wool Waste-Fibers: Influence of Body Region

by Corina Sosdean, Susana Piçarra, Sergiu-Valentin Galatanu and Liviu Marsavina

Eng. Proc. 2025, 119(1), 17; https://doi.org/10.3390/engproc2025119017 - 12 Dec 2025

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Abstract

Europe produces over 200,000 tons of coarse wool annually, a material often undervalued despite its potential in sustainable applications. This study investigates the mechanical behavior of individual “Țurcana” wool fibers through tensile testing, with samples collected from different body regions of the same [...] Read more.

Europe produces over 200,000 tons of coarse wool annually, a material often undervalued despite its potential in sustainable applications. This study investigates the mechanical behavior of individual “Țurcana” wool fibers through tensile testing, with samples collected from different body regions of the same sheep. Complementary SEM and FTIR analyses were employed to characterize the morphology and chemical constitution of the fibers. The results revealed clear differences in mechanical performance and morphology among fibers from different regions, as well as variations within the same region, while slightly differences in chemical constitution were detected by ATR-FTIR across the body parts. Full article

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8 pages, 1658 KB

Open AccessProceeding Paper

Flexural Strength Investigation of Flat-Oriented PLA Filament 3D Printing Parts Under Different Infill Styles and Printing Conditions

by Nikolaos A. Fountas, John D. Kechagias, Stefanos Zaoutsos and Nikolaos M. Vaxevanidis

Eng. Proc. 2025, 119(1), 18; https://doi.org/10.3390/engproc2025119018 - 15 Dec 2025

Viewed by 341

Abstract

Fused filament fabrication (FFF) is a widely used material extrusion-based 3D printing process known for its cost-effectiveness, versatility, and ability to produce intricate components. However, the strength of interlayer bonding is significantly influenced by printing parameters, material characteristics, and the chosen printing paths. [...] Read more.

Fused filament fabrication (FFF) is a widely used material extrusion-based 3D printing process known for its cost-effectiveness, versatility, and ability to produce intricate components. However, the strength of interlayer bonding is significantly influenced by printing parameters, material characteristics, and the chosen printing paths. The present study employs a custom response surface design derived from an L9 orthogonal array to strictly investigate the impact of three distinct infill patterns under varying printing temperatures and printing speeds on the responses of flexural strength, σ_b, and elasticity modulus, E (MPa). Flat-oriented poly-lactic acid (PLA) specimens were subjected to three-point bending tests to evaluate flexural strength for 100% infill rates and a 0.2 mm layer height. Besides the experimental investigation and the statistical analysis, failure modes of the fractured samples were observed to correlate the independent printing parameters with the aforementioned response. The desirability function was employed to identify the set of optimal parameters for maximizing the flexural strength and elasticity modulus for the particular PLA material brand examined. The results indicated that infill pattern and printing speed have significant impact on both responses. The optimal parameters were identified as “centroid” for infill style, 203.03 °C for printing temperature and 25 mm/s for printing speed. Full article

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8 pages, 2335 KB

Open AccessProceeding Paper

Intralaminar Fracture Calibration of Fabric Material Card for Non-Local Damage Crash Modelling

by Maria Pia Falaschetti, Francesco Semprucci, Johan Birnie Hernández, Luca Raimondi, Enrico Troiani and Lorenzo Donati

Eng. Proc. 2025, 119(1), 19; https://doi.org/10.3390/engproc2025119019 - 15 Dec 2025

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Abstract

Crashworthiness refers to a structure’s ability to absorb and dissipate impact energy through controlled deformation, thereby enhancing protection of vehicle occupants and onboard equipment. Composite materials possess significant potential in crashworthy airborne and ground vehicle structures due to their favourable specific energy absorption. [...] Read more.

Crashworthiness refers to a structure’s ability to absorb and dissipate impact energy through controlled deformation, thereby enhancing protection of vehicle occupants and onboard equipment. Composite materials possess significant potential in crashworthy airborne and ground vehicle structures due to their favourable specific energy absorption. However, their performance depends on several design factors such as materials, stacking sequences, and geometry. To reduce development costs and time to market, numerical simulations have become a necessary tool for optimising these factors. A challenge in this approach is the calibration of models, which is decisive for ensuring reliable and predictive simulations. Among other approaches, Non-local Damage Models have demonstrated reliability in simulating crashworthy composite structures. This work presents the intralaminar fracture energy calibration of fabric ply within a Waas–Pineda model, as implemented in ESI Virtual Performance Solutions, using Compact Tension and Compact Compression tests. Full article

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9 pages, 2175 KB

Open AccessProceeding Paper

On the Development of a Deep Learning-Based Surrogate Model for Fleet-Wide Probabilistic Modeling

by Georgios Aravanis, Marco Giglio and Claudio Sbarufatti

Eng. Proc. 2025, 119(1), 20; https://doi.org/10.3390/engproc2025119020 - 15 Dec 2025

Viewed by 460

Abstract

High-fidelity numerical models are widely used to study the behavior of complex structures in Structural Health Monitoring (SHM), but their high computational cost limits their use in stochastic settings such as fleet-level applications. In practice, fleets of engineering assets show natural variability due [...] Read more.

High-fidelity numerical models are widely used to study the behavior of complex structures in Structural Health Monitoring (SHM), but their high computational cost limits their use in stochastic settings such as fleet-level applications. In practice, fleets of engineering assets show natural variability due to differences in loading, materials, and manufacturing, making them inherently stochastic. To address these challenges, this work develops a probabilistic surrogate model based on conditional variational autoencoders (CVAEs). The CVAE is trained to reconstruct the high-dimensional boundary response field of a critical structural region while explicitly conditioning on operational and structural parameters. By learning a latent probabilistic representation, the model explains the behavior of all individual members of a homogeneous population. Synthetic training and testing data are generated using a finite element model together with an aerodynamic panel model of a UAV. Results show that the CVAE can efficiently reproduce the spatial and stochastic features of the system response, providing accurate approximations at a fraction of the computational cost of high-fidelity simulations. Full article

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9 pages, 1893 KB

Open AccessProceeding Paper

Post-Corrosion Repair Thickness Measurements Using Lamb-Wave Technology: An Aviation MRO Case Study

by Maria Zilidou, Jan-Willem Vrolijk, Robert Poppe, Roel van der Velde, Marco Mout, Emiel Hassefras, Daniel Friesen, Konstantinos Stamoulis, Luca Brugaletta and Quincy Martina

Eng. Proc. 2025, 119(1), 21; https://doi.org/10.3390/engproc2025119021 - 16 Dec 2025

Viewed by 231

Abstract

Routine maintenance of commercial aircraft requires reliable detection and repair of corrosion to ensure structural integrity. Post-repair inspections are commonly performed using manual ultrasonic point measurements of residual thickness, a process that is time-intensive and constrained by limitations in accuracy, repeatability, and cost. [...] Read more.

Routine maintenance of commercial aircraft requires reliable detection and repair of corrosion to ensure structural integrity. Post-repair inspections are commonly performed using manual ultrasonic point measurements of residual thickness, a process that is time-intensive and constrained by limitations in accuracy, repeatability, and cost. This study reports initial results of a non-contact, ultrasonic Lamb-wave-based inspection method, implemented with a mobile prototype system. The prototype integrates scanning, data acquisition, and reporting into a mobile workstation to support automated corrosion-repair inspections. Field trials validated the underlying measurement principle, while highlighting challenges when subsurface structures interfere with skin-only thickness evaluation. Full article

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8 pages, 2995 KB

Open AccessProceeding Paper

Early Detection, Evaluation and Continuous Monitoring of Hydrogen-Induced Cracking in Oil and Gas Vessels

by Dimitrios Kourousis, Dimitrios Papasalouros and Athanasios Anastasopoulos

Eng. Proc. 2025, 119(1), 22; https://doi.org/10.3390/engproc2025119022 - 15 Dec 2025

Viewed by 221

Abstract

Hydrogen-Induced Cracking (HIC) and Stress-Oriented Hydrogen-Induced Cracking (SOHIC) pose a significant threat to the integrity of steel components in wet H₂S service within the refining industry. This paper presents an integrated approach to HIC and SOHIC management, combining state-of-the-art inspection and [...] Read more.

Hydrogen-Induced Cracking (HIC) and Stress-Oriented Hydrogen-Induced Cracking (SOHIC) pose a significant threat to the integrity of steel components in wet H₂S service within the refining industry. This paper presents an integrated approach to HIC and SOHIC management, combining state-of-the-art inspection and monitoring techniques leading to Fitness-for-Service (FFS) assessments. Specifically, it details the synergistic application of Phased Array Ultrasonic Testing (PAUT) for precise crack detection and characterization and Acoustic Emission (AE) monitoring for real-time damage evolution insights. A key innovation is the development of in-house software capable of automatically clustering HIC and SOHIC PAUT data. An illustrative case study, referring to six months of continuous operational data and advanced re-analysis, demonstrates the practical application and benefits of this approach for predictive maintenance. To the authors’ knowledge, this constitutes the first continuous in-service correlation between real-time AE activity and PAUT-sized HIC damage, providing geometric input for API 579/ASME FFS-1 assessments, minimizing downtime, and mitigating failure risks. Full article

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8 pages, 1619 KB

Open AccessProceeding Paper

Modeling Tensile Properties in Selective Laser Melting of 316L Stainless Steel Using Statistical Multi-Parameter Analysis and Artificial Neural Networks

by Ioannis Papantoniou, Nikolaos A. Fountas, Dimitrios E. Manolakos and Nikolaos M. Vaxevanidis

Eng. Proc. 2025, 119(1), 23; https://doi.org/10.3390/engproc2025119023 - 16 Dec 2025

Viewed by 222

Abstract

Selective Laser Melting (SLM) of 316L stainless steel was studied with a focus on the combined influence of laser power and scan speed on tensile behavior. A full factorial design generated 27 experiments, and mechanical properties (yield stress, ultimate tensile strength, elongation, and [...] Read more.

Selective Laser Melting (SLM) of 316L stainless steel was studied with a focus on the combined influence of laser power and scan speed on tensile behavior. A full factorial design generated 27 experiments, and mechanical properties (yield stress, ultimate tensile strength, elongation, and Young’s modulus) were analyzed using analysis of variance (ANOVA) and quadratic regression models. Artificial Neural Networks (ANNs) were trained on selected datasets to capture nonlinear dependencies, achieving excellent predictive accuracy (R² > 0.998). Fractographic observations validated the trends, confirming ductile fracture at low scan speeds and brittle behavior at high scan speeds. Full article

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9 pages, 1442 KB

Open AccessProceeding Paper

Lifetime-Centric Engineering Approach for Fiber-Reinforced Polymer Springs Regarding Fatigue and Material Degradation

by Martin Petrich and Ulf Kletzin

Eng. Proc. 2025, 119(1), 24; https://doi.org/10.3390/engproc2025119024 - 16 Dec 2025

Viewed by 177

Abstract

Fiber-reinforced plastics (FRP) have been established as spring materials for specific applications for decades. In addition to their material advantages, the associated characteristics of strength and stiffness loss due to fatigue and degradation must also be considered. For FRP springs, the stiffness loss [...] Read more.

Fiber-reinforced plastics (FRP) have been established as spring materials for specific applications for decades. In addition to their material advantages, the associated characteristics of strength and stiffness loss due to fatigue and degradation must also be considered. For FRP springs, the stiffness loss gains importance because of functional relevance. This article focusses on the lifetime design of FRP springs from this perspective, based on the assumption that a service range develops over time and load cycles in which the spring exhibits the desired functional characteristics. This approach was investigated on FRP strip specimens subjected to torsional loading, as well as on GFRP and CFRP volute springs. The expected behaviors were confirmed, and modeling approaches for future applications were identified. Full article

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8 pages, 2266 KB

Open AccessProceeding Paper

A Fatigue Life Calculation Procedure Implementing Surface and Depth-Graded Mechanical Properties

by Paschalis Adamidis, Christos Gakias, Efstratios Giannakis and Georgios Savaidis

Eng. Proc. 2025, 119(1), 25; https://doi.org/10.3390/engproc2025119025 - 11 Dec 2025

Viewed by 191

Abstract

This study presents a fatigue life prediction procedure for high-strength steel suspension components that exhibit surface and depth-graded mechanical properties due to manufacturing processes such as shot peening and heat treatment. A layer-by-layer approach based on local stress and material properties at the [...] Read more.

This study presents a fatigue life prediction procedure for high-strength steel suspension components that exhibit surface and depth-graded mechanical properties due to manufacturing processes such as shot peening and heat treatment. A layer-by-layer approach based on local stress and material properties at the examined depth from the surface is implemented, allowing the generation of S-N curves that reflect the local fatigue response at different depths. The methodology is applied to a parabolic monoleaf spring for the axle suspension of commercial vehicles, made of 51CrV4 steel, and validated against experimental fatigue data. Results show strong agreement, demonstrating the effectiveness of incorporating local mechanical characteristics in terms of stress and material properties into fatigue design workflows. Full article

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9 pages, 1886 KB

Open AccessProceeding Paper

On the Optimization of Additively Manufactured Part Quality Through Process Monitoring: The Wire DED-LB Case

by Konstantinos Tzimanis, Michail S. Koutsokeras, Nikolas Porevopoulos and Panagiotis Stavropoulos

Eng. Proc. 2025, 119(1), 26; https://doi.org/10.3390/engproc2025119026 - 17 Dec 2025

Viewed by 243

Abstract

The wire Laser-based Directed Energy Deposition (DED-LB) metal additive manufacturing (AM) process is time- and cost-effective, providing high-quality, dense parts while supporting multi-scale manufacturing, repair, and repurposing services. However, its ability to consistently produce parts of uniform quality depends on process stability, which [...] Read more.

The wire Laser-based Directed Energy Deposition (DED-LB) metal additive manufacturing (AM) process is time- and cost-effective, providing high-quality, dense parts while supporting multi-scale manufacturing, repair, and repurposing services. However, its ability to consistently produce parts of uniform quality depends on process stability, which can be achieved through monitoring and controlling key process phenomena, such as heat accumulation and variations in the distance between the deposition head and the working surface (standoff distance). Part quality is closely linked to achieving predictable melt pool dimensions and stable thermal conditions, which in turn influence the end-part’s cross-sectional stability, overall dimensions, and mechanical properties. This work presents a workflow that correlates process and metrology data, enabling the determination of tunable process parameters and their operating process window. The process data are acquired using a vision-based monitoring system and a load-cell embedded in the deposition head, which together detect variations in melt pool area and standoff distance during the process, while metrology devices assess the part quality. Finally, this monitoring setup and its ability to capture the complete process history are fundamental for developing in-line control strategies, enabling optimized, supervision-free, and repeatable processes. Full article

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8 pages, 3026 KB

Open AccessProceeding Paper

Fatigue Performance of Hot-Formed Automotive Antiroll Bars

by Christos Gakias, Efstratios Giannakis, Paschalis Adamidis, Yucheng Wang and Georgios Savaidis

Eng. Proc. 2025, 119(1), 27; https://doi.org/10.3390/engproc2025119027 - 17 Dec 2025

Viewed by 158

Abstract

This study investigates the fatigue life of heat-treated and shot-peened antiroll bars used in heavy-duty truck suspensions. These components enhance vehicle stability by increasing torsional stiffness. Experimental tests, including microstructure inspection, hardness, and roughness measurements, assess material properties and manufacturing effects such as [...] Read more.

This study investigates the fatigue life of heat-treated and shot-peened antiroll bars used in heavy-duty truck suspensions. These components enhance vehicle stability by increasing torsional stiffness. Experimental tests, including microstructure inspection, hardness, and roughness measurements, assess material properties and manufacturing effects such as decarburization and shot peening. Subjected to multiaxial proportional loading, the bars present complex fatigue behavior. The study focuses on fatigue life influencing factors and the determination of S-N curves for the fatigue-based design of full-scale components. Full article

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8 pages, 1638 KB

Open AccessProceeding Paper

Design of Novel HS/HC/HT Twitch Aluminum Alloys

by Maria-Ioanna T. Tzini and Gregory B. Olson

Eng. Proc. 2025, 119(1), 28; https://doi.org/10.3390/engproc2025119028 - 18 Dec 2025

Viewed by 182

Abstract

The design of novel high-strength (HS), high-electrical-conductivity (HC) and high-thermostability (HT) aluminum alloys is presented utilizing recycled automotive aluminum twitch for cable conductor applications. Calculation of phase diagrams (CALPHAD)-based tools are employed for the design, with key objectives being the enhancement of electrical [...] Read more.

The design of novel high-strength (HS), high-electrical-conductivity (HC) and high-thermostability (HT) aluminum alloys is presented utilizing recycled automotive aluminum twitch for cable conductor applications. Calculation of phase diagrams (CALPHAD)-based tools are employed for the design, with key objectives being the enhancement of electrical conductivity through the complete gettering of impurity elements and the optimization of precipitation strengthening through the promotion of Q phase and the suppression of Si phase. The experimental data suggests that thermodynamic equilibrium conditions have not been reached yet under the tested annealing conditions, and models show that Si has the largest impact on electrical resistivity sensitivity. Full article

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8 pages, 2050 KB

Open AccessProceeding Paper

Design and Construction of a Floating Wind Turbine Scale Model with Composite Materials and Its Integration into Gravity-Based Offshore Structures

by Dimitrios A. Bartziokas, Thomas P. Mazarakos, Isidoros Iakovidis and Sotiria Dimitrellou

Eng. Proc. 2025, 119(1), 29; https://doi.org/10.3390/engproc2025119029 - 18 Dec 2025

Viewed by 314

Abstract

The present paper deals with the design and construction of a floating wind turbine (WT) scale model, using composite materials and additive manufacturing technology, and its subsequent integration into offshore gravity-based structures (GBS). The 5MW wind turbine model (pylon, blades, nacelle, and hub) [...] Read more.

The present paper deals with the design and construction of a floating wind turbine (WT) scale model, using composite materials and additive manufacturing technology, and its subsequent integration into offshore gravity-based structures (GBS). The 5MW wind turbine model (pylon, blades, nacelle, and hub) is made of composite material, with the aim of placing it in a GBS. The dimensions of the scaled model have been selected based on the experimental tank at the University of West Attica, which was used to conduct the required tests. To ensure the stability and reliability of the wind turbine support base, hydrodynamic loads caused by sea waves were calculated using analytical methods. Full article

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9 pages, 1374 KB

Open AccessProceeding Paper

Correlation of Normalized Strain from Image-Based Techniques with Optical Fiber Sensors Measurements in Mechanically Stabilized Earth Systems: Insights from Scaled Physical Modeling in a Geotechnical Centrifuge

by Elena Kapogianni and Alexander Savaidis

Eng. Proc. 2025, 119(1), 30; https://doi.org/10.3390/engproc2025119030 - 18 Dec 2025

Viewed by 188

Abstract

This study investigates the correlation between strains obtained from the image-based technique GeoPIV and Fiber Bragg Grating (FBG) sensors’ measurements in Mechanically Stabilized Earth (MSE) systems, using scaled physical modeling in a geotechnical centrifuge. FBG sensors provide high-resolution, localized strain data along reinforcements, [...] Read more.

This study investigates the correlation between strains obtained from the image-based technique GeoPIV and Fiber Bragg Grating (FBG) sensors’ measurements in Mechanically Stabilized Earth (MSE) systems, using scaled physical modeling in a geotechnical centrifuge. FBG sensors provide high-resolution, localized strain data along reinforcements, while GeoPIV offers full-field visualization of soil deformation. By calibrating GeoPIV outputs to microstrains, the complementary strengths of the two approaches are highlighted. In addition, the centrifuge setup reproduces realistic stress conditions, enhancing experimental reliability. The combined use of these methods not only improves understanding and monitoring of MSE behavior but also demonstrates strong potential for broader application in other laboratory-scale studies. Full article

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8 pages, 20753 KB

Open AccessProceeding Paper

Determination of Fatigue Crack Size in High-Strength Bolting Assemblies Using Hydrogen-Induced Cracking

by Fritz Wegener, Ralf Glienke, Daniela Schwerdt, Mathias Lorenz, Justus Mantik and Wilko Flügge

Eng. Proc. 2025, 119(1), 31; https://doi.org/10.3390/engproc2025119031 - 19 Dec 2025

Cited by 1 | Viewed by 289

Abstract

For the validation of approaches like fracture mechanics used for the description of crack propagation in high-strength bolting assemblies, it is often necessary to determine the size of an existing crack in the tested assembly. However, since the fatigue crack typically initiates in [...] Read more.

For the validation of approaches like fracture mechanics used for the description of crack propagation in high-strength bolting assemblies, it is often necessary to determine the size of an existing crack in the tested assembly. However, since the fatigue crack typically initiates in the root of the first load bearing thread, it is not directly accessible during fatigue testing. The crack size determination method presented here achieves further propagation of the original fatigue crack after the fatigue test by hydrogen-induced cracking under constant load. The characteristic microstructure of the resulting fracture surface then allows for the determination of the original crack size. In the present study, the fatigue crack sizes in M12 bolting assemblies are determined and a corresponding linear elastic fracture mechanics model is validated. The presented method reliably leads to a failure in the plane of the original fatigue crack and allows for a precise measurement of the crack length. The validated fracture mechanics model describes the crack propagation reasonably well, taking into account the overall service life. Overall, the presented method is a valuable addition to existing crack size determination methods and a versatile tool in the further development of more advanced fracture mechanics models for high-strength bolting assemblies. Full article

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6 pages, 1381 KB

Open AccessProceeding Paper

Influence of Impurities on the Hot Shortness of Brass Alloys

by Vasilis Loukadakis, Eleni Skepetzaki, Marianthi Bouzouni and Spyros Papaefthymiou

Eng. Proc. 2025, 119(1), 32; https://doi.org/10.3390/engproc2025119032 - 22 Dec 2025

Viewed by 238

Abstract

Brass alloys are critical for numerous modern applications. However, a significant knowledge gap exists regarding the impact of impurities on their processability, particularly regarding hot cracking susceptibility. This issue is exacerbated by increasing recycling rates, leading to a higher concentration of impurities in [...] Read more.

Brass alloys are critical for numerous modern applications. However, a significant knowledge gap exists regarding the impact of impurities on their processability, particularly regarding hot cracking susceptibility. This issue is exacerbated by increasing recycling rates, leading to a higher concentration of impurities in the alloy pool. This study employed computational thermodynamics to assess the impact of common impurities in brasses. Based on the results, the combined impact of impurities and alloying content significantly shifted the α and β solvus to the left, the α solvus indicatively is shifted by approximately 10% at low temperatures, and introduced multiple solvus and liquidus lines, crucial for the hot formability of the alloy. These preliminary results provide insight on the need for process optimization, considering the possibly deleterious effects of some elements to minimize the risk of hot cracking, a step towards enhancing the reliability and sustainability of these alloys. Full article

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8 pages, 2232 KB

Open AccessProceeding Paper

Fatigue of Additively Manufactured 18Ni300 Maraging Steel

by Antonios Tsakiris, Ioannis Foroglou, Paschalis Adamidis and Georgios Savaidis

Eng. Proc. 2025, 119(1), 33; https://doi.org/10.3390/engproc2025119033 - 22 Dec 2025

Viewed by 229

Abstract

This study thoroughly investigates the fatigue behavior and properties of additively manufactured (AM) 18Ni300 maraging steel, crucial for the design of load-carrying engineering components. Thin-walled flat specimens, produced via Selective Laser Melting (SLM), underwent a specific thermal process of annealing and aging. Extensive [...] Read more.

This study thoroughly investigates the fatigue behavior and properties of additively manufactured (AM) 18Ni300 maraging steel, crucial for the design of load-carrying engineering components. Thin-walled flat specimens, produced via Selective Laser Melting (SLM), underwent a specific thermal process of annealing and aging. Extensive monotonic and cyclic tests (R = 0.1) were conducted to determine static and fatigue material properties. Optical microscopy revealed the thermal process’s effect on microstructure. Experimentally determined design S-N curves, covering low-cycle to engineering endurance limits, allowed estimation of fundamental elastoplastic properties. This work provides valuable new insights and experimentally verified data, addressing a significant literature gap and supporting advanced fatigue-based design for AM components. Full article

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9 pages, 1492 KB

Open AccessProceeding Paper

Predicting Fatigue-Driven Delamination in Curved Composite Laminates Under Non-Constant Mixed-Mode Conditions Using a VCCT-Based Approach

by Carlos Mallor, Mario Sanchez, Andrea Calvo, Susana Calvo, Hubert Roman-Wasik and Federico Martin de la Escalera

Eng. Proc. 2025, 119(1), 34; https://doi.org/10.3390/engproc2025119034 - 19 Dec 2025

Viewed by 227

Abstract

Carbon-fibre reinforced polymer (CFRP) laminates are susceptible to both static and fatigue-driven delamination. Predicting this type of failure in curved composite structures, often referred to as delamination by unfolding, remains a critical challenge. This work presents the development of a Virtual Crack Closure [...] Read more.

Carbon-fibre reinforced polymer (CFRP) laminates are susceptible to both static and fatigue-driven delamination. Predicting this type of failure in curved composite structures, often referred to as delamination by unfolding, remains a critical challenge. This work presents the development of a Virtual Crack Closure Technique (VCCT)-based computational method for simulating fatigue-driven delamination propagation under non-constant mixed-mode conditions. The fatigue delamination growth model follows a phenomenological approach based on a Paris–Erdogan-based power-law relationship, where the delamination propagation rate depends on the strain energy release rate. This methodology has been implemented as a user-defined subroutine, UMIXMODEFATIGUE, for Abaqus, integrating the effects of load ratio and mode mixity conditions while leveraging the mode separation provided by VCCT. The proposed approach is validated against an experimental case involving a four-point bending test applied to an L-shaped CFRP curved beam specimen with a unidirectional layup. Unlike the existing standard configuration, the proposed test campaign introduces a non-adhesive Teflon foil insert at the bend, placed within the midplane layers to act as a delamination initiator, representing a manufacturing defect. In addition to the testing machine, digital image correlation (DIC) is used to monitor delamination length. The simulation method developed accurately predicts fatigue delamination propagation under varying mode mixity at the delamination front. By improving delamination modelling in composites, this approach supports timely maintenance and helps prevent fatigue failures. Additionally, it deepens the understanding of how the mode mixity influences the delamination propagation process. Full article

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8 pages, 1678 KB

Open AccessProceeding Paper

Preliminary Evaluation of the Crashworthiness Properties of Sandwich Composite Panels with 3D Printed Cores

by Maria Pia Falaschetti, Francesco Semprucci and Genevieve Palardy

Eng. Proc. 2025, 119(1), 35; https://doi.org/10.3390/engproc2025119035 - 22 Dec 2025

Viewed by 249

Abstract

In recent years, sandwich composite panels have gained significant attention due to their high strength-to-weight ratio, excellent energy absorption capability, and structural efficiency under impact and crash conditions. These panels, which consist of lightweight cores enclosed between stiff face sheets, are widely used [...] Read more.

In recent years, sandwich composite panels have gained significant attention due to their high strength-to-weight ratio, excellent energy absorption capability, and structural efficiency under impact and crash conditions. These panels, which consist of lightweight cores enclosed between stiff face sheets, are widely used in aerospace, automotive, and marine applications. Previous research on energy absorption mechanisms, failure modes, and the influence of core materials on crash performance has highlighted the advantages of various core configurations in improving Specific Energy Absorption (SEA). Among these, 3D-printed cores stand out for their design flexibility, efficient manufacturing process, and ability to customise mechanical properties through geometric optimisation. The present study investigates the crash behaviour of sandwich composite panels with 3D-printed polylactic acid (PLA) cores by examining different core geometries and configurations through an experimental campaign. Full article

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8 pages, 2422 KB

Open AccessProceeding Paper

On the Developing Network of Adiabatic Shear Bands During High Strain-Rate Forging Process: A Parametric Study on the Effect of Specimen Aspect Ratio

by Konstantina D. Karantza and Dimitrios E. Manolakos

Eng. Proc. 2025, 119(1), 36; https://doi.org/10.3390/engproc2025119036 - 23 Dec 2025

Viewed by 211

Abstract

The present work studies the developing network of adiabatic shear bands (ASBs) during dynamic plane strain compression of orthogonal AISI 1045 steel billets, aiming to investigate the ASB trajectories and their evolution mechanism. This paper conducts a finite element (FE) numerical analysis in [...] Read more.

The present work studies the developing network of adiabatic shear bands (ASBs) during dynamic plane strain compression of orthogonal AISI 1045 steel billets, aiming to investigate the ASB trajectories and their evolution mechanism. This paper conducts a finite element (FE) numerical analysis in LS-DYNA software, developing a doubly coupled analysis by combining both structural–thermal and structural–damage couplings. The Modified Johnson–Cook (MJC) formulas are considered for modeling both the material plasticity and damage law, implementing thermo-viscoplastic numerical approaches, while a critical temperature for material failure is further adjusted. Finally, the case study relates to a parametric analysis of specimen aspect ratio, aiming to reveal its effect on the developing ASB network and its propagating characteristics. Full article

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9 pages, 1830 KB

Open AccessProceeding Paper

Adopting Multi-Material Wire DED-LB in Naval Industry: A Case Study in Stainless Steel and Nickel-Based Alloys

by Konstantinos Tzimanis, Nikolas Gavalas, Nikolas Porevopoulos and Panagiotis Stavropoulos

Eng. Proc. 2025, 119(1), 37; https://doi.org/10.3390/engproc2025119037 - 23 Dec 2025

Viewed by 186

Abstract

Multi-material Directed Energy Deposition (DED) Additive Manufacturing (AM) processes enable the integration of different material properties into a single structure, addressing the requirements of various applications and working environments. Laser-based Directed Energy Deposition (DED-LB) has been employed in the past for surface coatings [...] Read more.

Multi-material Directed Energy Deposition (DED) Additive Manufacturing (AM) processes enable the integration of different material properties into a single structure, addressing the requirements of various applications and working environments. Laser-based Directed Energy Deposition (DED-LB) has been employed in the past for surface coatings as well as for the repair and repurposing of high-value industrial components, with the goal of extending product lifetime without relying on expensive and time-consuming manufacturing from scratch. While powder DED-LB has traditionally been used for multi-material AM, the more resource-efficient and cost-effective wire DED-LB process is now being explored as a solution for creating hybrid materials. This work focuses on the critical aspects of implementing multi-material DED-LB, specifically defining an optimal operating process window that ensures the best quality and performance of the final parts. By investigating the possibility of combining stainless steel and nickel-based alloys, this study seeks to unlock new possibilities for the repair and optimization of naval components, ultimately improving operational efficiency and reducing downtime for critical naval equipment. The analysis of the experimental results has revealed strong compatibility of stainless steel 316 with Inconel 718 and stainless steel 17-4PH, while the gray cast iron forms acceptable fusion only with stainless steel 17-4PH. Finally, during the experimental phase, substrate pre-heating and process monitoring with thermocouples will be employed to manage and assess heat distribution in the working area, ensuring defect-free material joining. Full article

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8 pages, 3196 KB

Open AccessProceeding Paper

Development of a Method for Monitoring the Condition of Remotely Controlled Demolition Robot to Prevent Structural Failures

by Damian Derlukiewicz and Jakub Andruszko

Eng. Proc. 2025, 119(1), 38; https://doi.org/10.3390/engproc2025119038 - 23 Dec 2025

Viewed by 179

Abstract

This paper presents a methodology for monitoring the structural condition of remotely controlled demolition robots to prevent failures and extend service life. The approach integrates finite element method (FEM) simulations with strain gauge and vibroacoustic measurements. Iterative calibration of numerical models enabled accurate [...] Read more.

This paper presents a methodology for monitoring the structural condition of remotely controlled demolition robots to prevent failures and extend service life. The approach integrates finite element method (FEM) simulations with strain gauge and vibroacoustic measurements. Iterative calibration of numerical models enabled accurate mapping of stress distribution, while optimal sensor placement improved monitoring precision. The study examined the impact of operational loads on durability and vibration resistance of critical components. The developed system enhances safety, operational efficiency, and structural reliability, providing a practical framework for predictive maintenance of demolition robots. Full article

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8 pages, 1586 KB

Open AccessProceeding Paper

On the Development of an Advanced Fatigue Testing Machine for Three-Point Bending of Polymer Matrix Composites

by Nikolaos Davaris, George-Christopher Vosniakos, Evangelos Tzimas and Emmanouil Stathatos

Eng. Proc. 2025, 119(1), 39; https://doi.org/10.3390/engproc2025119039 - 23 Dec 2025

Viewed by 222

Abstract

A crank press is converted into a smart fatigue testing machine for 3-point bending of polymer matrix composite specimens. The press is retrofitted with a load cell base for work holding, which monitors the bending force applied by the ram, a cycle counter [...] Read more.

A crank press is converted into a smart fatigue testing machine for 3-point bending of polymer matrix composite specimens. The press is retrofitted with a load cell base for work holding, which monitors the bending force applied by the ram, a cycle counter recording the number of loading cycles, and a camera recording snapshots of the specimen area where failure is expected. A convolutional and Resnet neural networks are trained to recognize failure as an area of color change in camera images. Signal drop on the load cell signals failure onset, thus triggering monitoring by the camera and execution of the neural network. Acceptable proof-of-concept results encourage further automation of the setup. Full article

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7 pages, 1320 KB

Open AccessProceeding Paper

A High-Accuracy 3D Simulation of Surface Shot Peening

by Christos Gakias, Efstratios Giannakis, Paschalis Adamidis, Stefan Dietrich, Volker Schulze and Georgios Savaidis

Eng. Proc. 2025, 119(1), 40; https://doi.org/10.3390/engproc2025119040 - 24 Dec 2025

Viewed by 224

Abstract

Shot peening is a widely used surface treatment method for improving fatigue life by inducing surface compressive residual stresses. In critical automotive components such as parabolic leaf springs, shot peening under pre-tension (stress shot peening) can further enhance durability. This study presents a [...] Read more.

Shot peening is a widely used surface treatment method for improving fatigue life by inducing surface compressive residual stresses. In critical automotive components such as parabolic leaf springs, shot peening under pre-tension (stress shot peening) can further enhance durability. This study presents a finite element model simulating stress peening in high-strength spring steels, incorporating realistic boundary conditions, material degradation due to decarburization, and stochastic shot properties, offering a high-accuracy yet computationally efficient alternative to extensive experimental testing. Results show that both below- and above-yield pre-stressing produce beneficial residual stresses, while the consideration on decarburization effects significantly alters surface stress fields. The model offers a reliable, time-efficient alternative to experiments for process and fatigue life optimization. Full article

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8 pages, 521 KB

Open AccessProceeding Paper

Buckling of Wide Rectangular GLARE Fiber-Metal Laminates Subjected to Compression

by Costas D. Kalfountzos, George S. E. Bikakis and Efstathios E. Theotokoglou

Eng. Proc. 2025, 119(1), 41; https://doi.org/10.3390/engproc2025119041 - 25 Dec 2025

Viewed by 209

Abstract

Fiber-Metal Laminates (FMLs) are hybrid composite structures of alternating metal layers and fiber-reinforced preimpregnated (prepreg) layers. The purpose of this article is to study numerically the elastic buckling behavior of simply supported FML plates compressed by two equal and opposite forces. More specifically, [...] Read more.

Fiber-Metal Laminates (FMLs) are hybrid composite structures of alternating metal layers and fiber-reinforced preimpregnated (prepreg) layers. The purpose of this article is to study numerically the elastic buckling behavior of simply supported FML plates compressed by two equal and opposite forces. More specifically, the main objective of the present study is the calculation of buckling coefficients of thin GLARE plates and the construction of diagrams of these coefficients as a function of their aspect ratio. It is found that the diagrams of the buckling coefficient versus the aspect ratio of aluminum and GLARE plates present a very similar trend. Full article

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7 pages, 2159 KB

Open AccessProceeding Paper

FGM Sandwich Curved Beam Under Thermomechanical Loads for Hydrogen Mechanical Applications

by Dimitrios A. Mallios, Efstathios E. Theotokoglou and Constantinos Chr. Koutsoumaris

Eng. Proc. 2025, 119(1), 42; https://doi.org/10.3390/engproc2025119042 - 29 Dec 2025

Viewed by 183

Abstract

In this study, a curved sandwich beam with Functionally Graded Materials (FGM) face sheets and a homogeneous core under thermomechanical loads is investigated. The problem is studied numerically by the finite element method (FEM). Plane, eight nodes isoparametric elements are used, where the [...] Read more.

In this study, a curved sandwich beam with Functionally Graded Materials (FGM) face sheets and a homogeneous core under thermomechanical loads is investigated. The problem is studied numerically by the finite element method (FEM). Plane, eight nodes isoparametric elements are used, where the gradient of the material properties is incorporated into the formulation of the element. The effect of the thickness and volume fraction index (VFI) of the FGM face sheets on the stress and the temperature fields are studied. The results are valuable in the design of hydrogen mechanical applications, since the FGM sandwich curved beam could be a part of hydrogen storage tanks. Full article

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9 pages, 2809 KB

Open AccessProceeding Paper

Hybrid Structural Health Monitoring for Impact Damage in PLA Plates Using SLDV and the Electromechanical Impedance Method

by Paresh Mirgal and Paweł H. Malinowski

Eng. Proc. 2025, 119(1), 43; https://doi.org/10.3390/engproc2025119043 - 30 Dec 2025

Viewed by 251

Abstract

With the growing use of 3D-printed polymers in structural applications, understanding their damage response under impact is critical for reliability and safety. This study investigates the impact response and damage progression in Fused Deposition Modelling (FDM)-printed Polylactic Acid (PLA) plates with varying infill [...] Read more.

With the growing use of 3D-printed polymers in structural applications, understanding their damage response under impact is critical for reliability and safety. This study investigates the impact response and damage progression in Fused Deposition Modelling (FDM)-printed Polylactic Acid (PLA) plates with varying infill densities (40%, 60%, and 100%) using a combination of scanning laser Doppler vibrometry (SLDV) and electromechanical impedance (EMI) techniques. Progressive impacts were applied in four stages, and damage was evaluated through wave attenuation, impedance deviation, and phase distortion metrics. Results show that lower infill densities exhibit more severe degradation, with increased damping and poor wave transmission, while 100% infill demonstrates higher damage resistance and better detectability. The findings underscore the importance of infill design in optimizing mechanical performance and structural health monitoring in additively manufactured components. Full article

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8 pages, 2499 KB

Open AccessProceeding Paper

Bending Behavior of the 95% and 99% Alumina Ceramics

by Sergiu-Valentin Galatanu, Victor Tiberiu Popi, Cosmin-Florin Popa and Liviu Marsavina

Eng. Proc. 2025, 119(1), 44; https://doi.org/10.3390/engproc2025119044 - 30 Dec 2025

Viewed by 189

Abstract

Alumina ceramics, known for their hardness, thermal resistance, and chemical stability, are widely applied in engineering and industry. This study investigates the flexural strength of 95% and 99% alumina ceramics using tubes with two or four cross-sectional holes, tested by 3-point and 4-point [...] Read more.

Alumina ceramics, known for their hardness, thermal resistance, and chemical stability, are widely applied in engineering and industry. This study investigates the flexural strength of 95% and 99% alumina ceramics using tubes with two or four cross-sectional holes, tested by 3-point and 4-point bending methods. Macroscopic analysis was performed with a Leica DM6M microscope to determine specimen areas and ensure measurement accuracy. Results indicate that 99% alumina ceramics exhibit approximately 35% higher bending strength compared to 95% alumina ceramics, highlighting the influence of alumina content on mechanical performance. Full article

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8 pages, 608 KB

Open AccessProceeding Paper

Fiber Metal Laminates for Battery Boxes: A Compromise Between Strength and Rigidity

by Claudio Mingazzini, Matteo Scafè, Edoardo Mariani, Giulia De Aloysio, Mattia Morganti, Luca Laghi, Leonardo Ghetti, Stefano Bassi and Cristiano Valli

Eng. Proc. 2025, 119(1), 45; https://doi.org/10.3390/engproc2025119045 - 30 Dec 2025

Viewed by 196

Abstract

Fiber Metal Laminates (FML), produced in both monolithic and sandwich configurations with glass-, basalt- and carbon-reinforced composites, were investigated for application in fire-resistant lithium battery boxes. Different resins, including recyclable and bio-based systems, were tested to improve sustainability; cores of recycled PET (RPET, [...] Read more.

Fiber Metal Laminates (FML), produced in both monolithic and sandwich configurations with glass-, basalt- and carbon-reinforced composites, were investigated for application in fire-resistant lithium battery boxes. Different resins, including recyclable and bio-based systems, were tested to improve sustainability; cores of recycled PET (RPET, 150 g/dm³, 10 mm) were considered. The study focused on the effect of core introduction on mechanical performance, with the dual goal of reducing weight and achieving stiffness values compliant with automotive OEM standards for lithium battery housings. Results demonstrated that sandwich structures improved stiffness up to 12-fold compared to monolithic laminates, while preserving the corrosion resistance of the outer aluminium layer and the flexural strength of the laminates after 670 h of Neutral Salt Spray (NSS) exposure. Full article

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8 pages, 2578 KB

Open AccessProceeding Paper

Influence of Graphite Degenerations on Mechanical Properties of Ductile Iron

by Tim Steingräber and Jan Niewiadomski

Eng. Proc. 2025, 119(1), 46; https://doi.org/10.3390/engproc2025119046 - 30 Dec 2025

Viewed by 185

Abstract

Ductile iron—also known as spheroidal graphite iron (SGI)—is a versatile material that exhibits a wide range of applications. In addition to the matrix structure itself, graphite morphology and material defects, such as graphite degenerations, also have a decisive influence on its mechanical properties. [...] Read more.

Ductile iron—also known as spheroidal graphite iron (SGI)—is a versatile material that exhibits a wide range of applications. In addition to the matrix structure itself, graphite morphology and material defects, such as graphite degenerations, also have a decisive influence on its mechanical properties. Missing or incomplete classifications of these deviating graphite morphologies in common standards, alongside insufficient knowledge regarding their effects, leads to a more complicated lifetime assessment and often results in rejection of SGI components. Therefore, relevant material parameters were derived from experimental quasi-static and fatigue investigations on SGI materials with different graphite degenerations and correlated with microstructural parameters quantified by an optimized digital image analysis method. While a linear correlation between the amount and mechanical properties was identified for spiky graphite, for chunky graphite, the presence in general can lead to a detrimental reduction in mechanical properties. Full article

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8 pages, 18297 KB

Open AccessProceeding Paper

Experimental Investigation on the Formation of Adiabatic Shear Bands (ASB) During Dynamic Compression of AISI 1045 Steel at Different Strain Rates

by Konstantina Karantza, Jari Rämö, Mikko Hokka and Dimitrios Manolakos

Eng. Proc. 2025, 119(1), 47; https://doi.org/10.3390/engproc2025119047 - 31 Dec 2025

Viewed by 190

Abstract

This study investigates the development of adiabatic shear bands (ASBs) in AISI 1045 carbon steel under high-strain-rate uniaxial compression, emphasizing the conditions governing their onset and growth. Split Hopkinson pressure bar (SHPB) experiments were carried out at strain rates of 1000, 2000 and [...] Read more.

This study investigates the development of adiabatic shear bands (ASBs) in AISI 1045 carbon steel under high-strain-rate uniaxial compression, emphasizing the conditions governing their onset and growth. Split Hopkinson pressure bar (SHPB) experiments were carried out at strain rates of 1000, 2000 and 4000 s⁻¹ with controlled displacement/strain interruption to capture gradual ASB formation throughout the process. Stress–strain data were analyzed alongside optical microscopy to determine the critical strain for ASB initiation, document ASB morphology, dimensions and type, and connect ASB formulating stages to material macroscopic mechanical behavior. The observations clarify how deformation evolves from homogenous plastic flow to localized shear instability as the strain and strain rate increase, linking mechanical response to microstructural features. Integrating these results, the effects of strain rate and strain progress on ASB formation and evolution characteristics are investigated. These findings enhance our understanding of shear localization phenomena under dynamic loading and provide a basis for predicting failure modes in structural applications. Full article

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7 pages, 2901 KB

Open AccessProceeding Paper

3D Modeling, Analysis, and Construction of an Exhaust System in a Formula Student Car

by Antonios Lontos and Andreas Gregoriou

Eng. Proc. 2025, 119(1), 48; https://doi.org/10.3390/engproc2025119048 - 4 Jan 2026

Viewed by 213

Abstract

This paper presents a new stainless-steel exhaust manifold system designed for a Formula Student racing car. The exhaust system meets the Formula Student regulations and is designed to be mounted on a 600 cc engine. Special consideration was given to the aspect of [...] Read more.

This paper presents a new stainless-steel exhaust manifold system designed for a Formula Student racing car. The exhaust system meets the Formula Student regulations and is designed to be mounted on a 600 cc engine. Special consideration was given to the aspect of fitment, due to the fact that the engine will fit on a steel tube chassis. The design of the exhaust system considers the importance of equal-length runners and the individual primary exhaust pipes of the header, which are ideal for increased engine performance. For the simulations, the ANSYS FLUENT 12 was employed. For the investigation of the exhaust gases’ characteristics, the governing equations of the k-ε model were employed. Full article

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8 pages, 2392 KB

Open AccessProceeding Paper

Guided Wave-Based Damage Detection Using Integrated PZT Sensors in Composite Plates

by Lenka Šedková, Ondřej Vích and Michal Král

Eng. Proc. 2025, 119(1), 49; https://doi.org/10.3390/engproc2025119049 - 7 Jan 2026

Viewed by 120

Abstract

The ultrasonic guided wave method is successfully used for structural health monitoring (SHM) of aircraft structures utilizing PZT (Pb-Zr-Ti based piezoceramic material) sensors for guided wave generation and detection. To increase the mechanical durability of the sensors in operational conditions, this paper demonstrates [...] Read more.

The ultrasonic guided wave method is successfully used for structural health monitoring (SHM) of aircraft structures utilizing PZT (Pb-Zr-Ti based piezoceramic material) sensors for guided wave generation and detection. To increase the mechanical durability of the sensors in operational conditions, this paper demonstrates the feasibility of the integration of PZTs into the Glass fiber/Polymethyl methacrylate (G/PMMA) composite plate and evaluates the possibility of impact damage detection using generated guided waves. Two types of PZT sensors were embedded into different layers during the manufacturing process. Generally, radial mode disc sensors are used for Lamb wave generation, and thickness-shear square-shaped sensors are used for both Lamb and shear wave generation. First, the wave propagation was analyzed considering the sensor type and sensor placement within the layup. The main objective was to propose the optimal sensor network with embedded sensors for successful impact damage detection. Lamb wave frequency tuning of disk sensors and unique vibrational characteristics of integrated shear sensors were exploited to selectively actuate only one guided wave mode. Finally, the Reconstruction Algorithm for the Probabilistic Inspection of Damage (RAPID) was utilized for damage localization and visualization. Full article

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8 pages, 1868 KB

Open AccessProceeding Paper

Experimental and Numerical Study of Mode II Fatigue Delamination via End-Loaded Split Specimens

by Johan Birnie, Maria Pia Falaschetti, Francesco Semprucci and Enrico Troiani

Eng. Proc. 2025, 119(1), 50; https://doi.org/10.3390/engproc2025119050 - 7 Jan 2026

Viewed by 137

Abstract

Delamination in fibre-reinforced polymer composites is a critical failure mechanism that can ultimately lead to a catastrophic failure. To characterise in-plane shear delamination (Mode II), several test setups have been proposed in the literature, with the End-Loaded Split (ELS) test being the most [...] Read more.

Delamination in fibre-reinforced polymer composites is a critical failure mechanism that can ultimately lead to a catastrophic failure. To characterise in-plane shear delamination (Mode II), several test setups have been proposed in the literature, with the End-Loaded Split (ELS) test being the most suitable for applications that require stable crack propagation (ISO 15114). This manuscript focuses on studying Mode II fatigue delamination in unidirectional carbon fibre-reinforced laminates using the ELS configuration. Experimental tests with varying displacement ratios and different initial energy levels were conducted to capture a wide range of stable crack propagation scenarios. To complement these experimental efforts, a numerical model based on cohesive zone models (CZM) was implemented in Abaqus, utilising a user-defined material subroutine (UMAT). The numerical results closely align with the experimental data, validating the model’s predictive capabilities. This combined approach deepens the understanding of Mode II fatigue delamination and provides a strong framework for designing and analysing composite structures. Full article

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8 pages, 2048 KB

Open AccessProceeding Paper

Methodology for Accurate Geometric Modeling of Filament Wound Structures

by Dimitrios A. Dragatogiannis and Panagiotis C. Christopoulos

Eng. Proc. 2025, 119(1), 51; https://doi.org/10.3390/engproc2025119051 - 9 Jan 2026

Viewed by 134

Abstract

Filament winding (FW) is a widely used automated manufacturing method for cylindrical composite structures. However, conventional modeling approaches often rely on oversimplified geometries, neglecting essential features such as fiber overlaps and gaps, which can affect the accuracy of subsequent mechanical analysis. In this [...] Read more.

Filament winding (FW) is a widely used automated manufacturing method for cylindrical composite structures. However, conventional modeling approaches often rely on oversimplified geometries, neglecting essential features such as fiber overlaps and gaps, which can affect the accuracy of subsequent mechanical analysis. In this work, we present a computational methodology for the accurate geometric reconstruction of FW components, based on the numerical calculation of fiber trajectories and their automated integration into CAD models. The proposed approach provides realistic geometrical representations that capture the actual fiber paths, enabling more reliable finite element simulations. Comparative results between the proposed method and traditional modeling techniques highlight key differences in stiffness prediction, demonstrating the importance of realistic geometric input for the mechanical analysis of filament-wound structures. Full article

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9 pages, 20916 KB

Open AccessProceeding Paper

Processing Optimization of the New Steel Grade 45SiCrV9Ni for Modern Leaf Springs in Battery Electric Vehicles

by Niki Nouri, Borja Escauriaza, Christos Gakias, Georgios Savaidis, Roberto Elvira, Stefan Dietrich and Volker Schulze

Eng. Proc. 2025, 119(1), 52; https://doi.org/10.3390/engproc2025119052 - 13 Jan 2026

Viewed by 151

Abstract

The optimization of battery electric vehicles requires advanced high-strength steels that combine ductility and toughness, enabling lightweight leaf spring constructions with improved performance. This study investigates processing optimization by comparing the newly developed 45SiCrV9Ni, previously identified as promising for stress peening and fatigue, [...] Read more.

The optimization of battery electric vehicles requires advanced high-strength steels that combine ductility and toughness, enabling lightweight leaf spring constructions with improved performance. This study investigates processing optimization by comparing the newly developed 45SiCrV9Ni, previously identified as promising for stress peening and fatigue, with the conventional 51CrV4 as a benchmark. Dilatometric, mechanical, and microstructural analyses were conducted in as-supplied and heat-treated conditions. Both steels show excellent high-temperature ductility, making them suitable for hot forming under similar conditions. However, 45SiCrV9Ni requires a higher temperature for homogenized austenitization. After tempering, it consistently exhibits superior hardness and toughness compared to 51CrV4. Importantly, its ductility remains nearly constant over a wide tempering temperature range, allowing lower ones to be chosen without compromising strength or toughness, offering additional energy-saving possibilities. These results highlight the potential of 45SiCrV9Ni for leaf spring applications. Full article

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8 pages, 1587 KB

Open AccessProceeding Paper

The Influence of Corrosion of Steel Reinforcement on the Shear Strength of Existing Structure and 2nd Degree Pre-Earthquake Inspection

by Maria Basdeki, Konstantinos Koulouris and Charis Apostolopoulos

Eng. Proc. 2025, 119(1), 53; https://doi.org/10.3390/engproc2025119053 - 9 Jan 2026

Viewed by 87

Abstract

The consequences of corrosion of steel reinforcement are recognized as one of the predominant degradation factors in the durability of Reinforced Concrete (RC) structures, negatively affecting their load-bearing capacity, ductility, and service lifetime. In light of structural aging, Greece has established methods for [...] Read more.

The consequences of corrosion of steel reinforcement are recognized as one of the predominant degradation factors in the durability of Reinforced Concrete (RC) structures, negatively affecting their load-bearing capacity, ductility, and service lifetime. In light of structural aging, Greece has established methods for inspecting and assessing its seismic adequacy prior to seismic events. However, although current scientific knowledge has considerably progressed in terms of quantifying corrosion damage of steel reinforcement, current regulations are now significantly lagging in adequately introducing the contribution of the corrosive factor in the assessment of existing structures’ seismic adequacy. Based on recent literature and the results of an extensive ongoing experimental research campaign (related to the corrosive factor), the present manuscript proposes interventions in the guidelines of the 2nd Degree Pre-Earthquake Inspection. Full article

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8 pages, 2479 KB

Open AccessProceeding Paper

Slip Effect on Rotational Capacity (Chord Rotation) of Corroded RC Members Due to Pull Out of Steel Reinforcement

by Konstantinos Koulouris, Maria Basdeki and Charis Apostolopoulos

Eng. Proc. 2025, 119(1), 54; https://doi.org/10.3390/engproc2025119054 - 14 Jan 2026

Viewed by 106

Abstract

Based on ongoing experimental research, the present manuscript presents the effect of the slippage of a steel reinforcing bar due to corrosion on the chord rotation and deformation of corroded Reinforced Concrete members. The experimental results recorded that the increase in the corrosion [...] Read more.

Based on ongoing experimental research, the present manuscript presents the effect of the slippage of a steel reinforcing bar due to corrosion on the chord rotation and deformation of corroded Reinforced Concrete members. The experimental results recorded that the increase in the corrosion level of the steel led to bond strength loss and relative slip between the steel and concrete, which was increased from 1.5 mm in non-corroded conditions to 3.5 mm even at low corrosion levels, up to a 5% steel mass loss. This slippage of corroded reinforcing bars from the anchorage leads to a proportional increase in terms of chord rotation due to pull out resulting in an additional increase in the displacement of the column’s top. In conclusion, the present study highlights the great importance of the contribution of the resulting slippage of a steel reinforcing bar due to corrosion in the calculation of the limit chord rotation (column–beam), a term which is of major importance in the assessment of the structural integrity of old RC structures, which was introduced as an adequacy requirement by both Eurocode 8-3 and the Greek Code of Structural Interventions (KAN.EPE). Full article

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9 pages, 1064 KB

Open AccessProceeding Paper

Probabilistic Algorithm for Waviness Defect Early Detection During High-Precision Bearing Manufacturing

by Sergio Noriega-del-Rivero, Jose-M. Rodriguez-Fortún and Luis Monzon

Eng. Proc. 2025, 119(1), 55; https://doi.org/10.3390/engproc2025119055 - 22 Jan 2026

Viewed by 82

Abstract

The grinding process of bearing components is a critical step in their manufacturing, as it directly impacts the functional properties of raceways and other critical surfaces. One important failure that arises during the grinding process is the appearance of waviness in the machined [...] Read more.

The grinding process of bearing components is a critical step in their manufacturing, as it directly impacts the functional properties of raceways and other critical surfaces. One important failure that arises during the grinding process is the appearance of waviness in the machined surface. This geometrical defect causes vibrations in operation with a consequent impact on power losses, noise and fatigue. The present work proposes an in-line detection system of waviness defects in bearing raceways. For this, the system uses accelerometers installed near the machined part and runs a detection algorithm in a local calculation unit. The results are sent over Ethernet to the central quality control of the line. The embedded algorithm uses the frequency content of the measured signal for predicting the surface quality of the final part. The prediction is performed by learning a non-parametric model describing the correspondence between the surface geometry and the measured vibration content. In order to obtain this model, a calibration process is conducted for each bearing reference, ensuring that the model accounts for the specific geometric and operational characteristics of the parts. By analyzing the correlation between accelerometer signals and harmonics, the algorithm predicts the probability of waviness occurrence. The proposed system has been implemented in a high-precision bearing production line, validating its effectiveness with multiple parts of the same reference. This approach identifies waviness during the machining process without the need for offline tests. This fact represents an improvement in the detection of defects, and it provides higher product quality and reduced operational costs. Full article

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