Search Results (3,370)

Ensuring the crashworthiness of heavy-duty truck cabs is essential for reducing occupant fatalities and improving passive safety in commercial vehicles. Regulatory frameworks such as UNECE Regulation No. 29 (R29) define structural integrity requirements through full-scale destructive impact tests, which are costly and limit iterative design. In this study, an integrated experimental–numerical methodology is presented for the impact assessment of a real Iveco Eurocargo 120E18 truck cab reconstructed using high-resolution 3D scanning. The scanned geometry was used to generate a dimensionally accurate CAD model of the load-bearing cab structure, which was analysed using explicit finite element simulations in ANSYS Academic Mechanical and CFD Teaching package under impact conditions compliant with UNECE R29 and implemented according to the Swedish regulation VVFS 2003:29. In parallel, a full-scale physical pendulum impact test was performed on the same cab using a cylindrical impactor with a diameter of 580 mm, a length of 1800 mm, and a mass of approximately 1000 kg, impacting the upper region of the A-pillar. The experimental setup was instrumented using high-speed optical measurements and an accelerometer to capture impact kinematics and structural response. The numerical predictions showed good agreement with experimental results in terms of acceleration–time histories, absorbed energy evolution, and structural deformation, with differences generally below 6%. Critical regions susceptible to local buckling and plastic collapse were consistently identified in both approaches, while preservation of the driver survival space was confirmed. The results demonstrate that scan-based finite element models, when properly calibrated and validated, can reliably reproduce certification-level impact behaviour. The proposed workflow provides a robust and cost-effective framework for regulatory pre-validation, structural optimisation, and digitalisation of crashworthiness assessment for heavy-duty truck cabs. Full article

This article mainly researches the model dimension reduction in the finite volume element (FVE) method based on proper orthogonal decomposition (POD) for the two-dimensional (2D) hyperbolic equation. For this objective, an FVE method with unconditional stability and second-order temporal accuracy, and the existence, stability, and error estimates of the FVE solutions are first reviewed. Thereafter, most importantly, a new FVF model dimension reduction (FVEMDR) formulation is established by applying POD technology to lower the dimension of the vectors composed of unknown coefficients for the FVE solutions. The greatest contribution of this article is the theoretical analysis of the existence, unconditional stability, and error estimations for the FVEMDR solutions. Moreover, in computation, two sets of numerical simulations are provided to confirm the validity of the theoretical results and show the effectiveness of the FVEMRD formulation. Full article

This paper investigates the design, analysis, and prototyping of a Flux-Switching Permanent Magnet (FSPM) motor for Formula SAE electric vehicle applications. The stringent competition requirements demand traction motors with high torque and power density, and reliable operation at elevated speeds. An analytical model based on air-gap permeance and magnetomotive force distributions is developed to provide an effective preliminary design tool and to reduce computational effort. The proposed model is used to define the main geometrical parameters of a 12-slot, 10-rotor-tooth FSPM machine, which is subsequently validated through finite element analysis. Analytical and numerical results are compared in terms of air-gap flux density, flux linkage, and torque capability, showing good agreement. Manufacturing-driven design choices, including optimized magnet slot geometry, laminated permanent magnets for eddy-current loss mitigation, and a mechanically robust lightweight rotor, are introduced to ensure high-speed operability and assembly reliability. Full article

This study presents a newly conducted comprehensive investigation into the lateral torsional buckling (LTB) behavior of un-bonded pre-stressed (PS) thin-walled steel I-beams subjected to non-uniform bending moments, combining a numerical study with a machine learning (ML) approach and experimental validation. Despite extensive prior work, no exact analytical solution exists particularly for non-uniform bending or can be extremely complicated, as the resulting differential equations contain variable coefficients particularly under non-uniform bending due to the complexity of the PS system. To overcome this limitation, a numerical study using finite element (FE) analysis is first conducted with emphasis on the key geometric and pre-stressing parameters, including unbraced beam length, tendon eccentricity, deviators configurations, and pre-stressing force, to evaluate the LTB behavior. The FE modeling was then validated against experimental testing to ensure the accuracy and reliability of the FE solutions. Subsequently, a comprehensive dataset is generated using FE simulations to train the ML models aimed at predicting the LTB resistance of the PS system. This study presents three ML approaches, including support vector regression (SVR), random forest (RF) and least-square boosting (LSBoost), and their optimal hyperparameters are determined using Bayesian optimization (BO) to enhance the prediction performance. The results indicate that the LTB capacity predicted by the Bayesian-optimized ML models achieve high predictive accuracy and are in close agreement with numerical FE simulations, thereby highlighting their potential in capturing the complex, underlying non-linear interactions influencing the buckling behavior of the PS structural system. Accordingly, the proposed framework offers a robust and effective predictive tool for evaluating LTB resistance, particularly under non-uniform bending where exact analytical solutions are not available, and for supporting the design and assessment of PS steel structures. Full article

The structural integrity of isolation dams in deep coal mines is critical to preventing underground disasters, particularly those involving water and waste-mixture inrushes. This study presents a forensic root-cause analysis, using reverse-engineering techniques, of a specific isolation-dam rupture to determine the failure mechanism under complex stress conditions and limited data availability. A hybrid investigative methodology was employed, combining sequential post-failure documentation analysis with physical-scale modelling and numerical simulations to reconstruct a deadly disaster for criminal investigation purposes. A 1:5 scale physical model of the excavation and dam was constructed using original construction materials to test the structure’s resistance to hydrostatic pressure. The experimental results demonstrated that the dam maintained integrity under static hydraulic loads representative of real-world conditions, with only minor seepage (“sweating”) and no structural failure over a 7-day monitoring period. To investigate external geomechanical factors, Finite Element Method (FEM) simulations were conducted using ANSYS software. The numerical analysis evaluated the effects of rock mass pressure and convergence on the dam’s stability. The results indicate that while the dam was designed to withstand significant hydraulic head, the failure was precipitated by excessive rock mass pressure at a depth of around 600 m, which induced critical stress concentrations exceeding the masonry’s load-bearing capacity. This study confirms that the dynamic rupture was driven by unforeseen geomechanical forces rather than hydrostatic overload alone, highlighting the necessity of considering rock mass–structure interaction in the safety assessment of underground isolation barriers. This approach enables mutual verification of the results obtained and reduces the ambiguity of interpretation that often accompanies the analysis of accident events in underground mining. It also confirms the application of tested methodology for mining disaster reconstruction as proof at the stage of investigation and in the Court. Full article

This study presents an ASME-based structural assessment of the head–shell junction in a 60 m³ pressurized railway tank wagon subjected to an internal pressure of 0.45 MPa, combining classical shell theory with finite element analysis (FEA) in accordance with ASME Section VIII Division 2 stress categorization and linearization procedures. An analytical model based on the moment theory of shells of revolution was developed to describe displacement and rotation compatibility at the ellipsoidal head–cylindrical shell junction, allowing for the determination of contour interaction loads governing membrane–bending coupling in the discontinuity region. The calculated contour loads (Q₀ = 795 N/mm, M₀ = 13,350 N·mm/mm) indicate localized membrane–bending interactions caused by geometric discontinuity. Finite element simulations using axisymmetric (2D) and full 3D models were evaluated through the ASME VIII-2 stress linearization procedure, enabling comparison between analytical predictions and numerical results. The maximum equivalent stress according to the Coulomb–Tresca criterion reached 115 MPa (2D) and 117 MPa (3D), with less than 2% deviation, confirming the adequacy of the axisymmetric model. Stress linearization shows that the maximum combined primary membrane and bending stress (109.5 MPa) remains well below the ASME allowable limit of 308 MPa, while the discontinuity influence zone extends approximately 120–150 mm from the junction. The results confirm compliance with ASME VIII Division 2 requirements and demonstrate that the combined analytical–numerical approach provides a reliable method for evaluating stress concentration effects in railway tank wagons. Full article

This study aims to address the acoustic resonance control problem of a three-dimensional nose landing gear (NLG) cavity. We propose a refined numerical approach based on an eigenvalue solver for the Helmholtz equation. A high-order finite element method (FEM) combined with perfectly matched layer (PML) boundary conditions was employed to accurately capture complex eigenmodes. The radiation damping characteristics of the system were then quantitatively characterized using the quality factor (Q-factor) and resonance frequency. Results indicate that the Helmholtz-type (0,0,0) mode dominates the cavity’s resonance response, with its frequency coinciding with the shear layer-driven Rossiter mode. This study reveals a strong coupling mechanism with the shear-layer-driven Rossiter mode at Mach 0.57, confirming that this interaction is the primary driver of cavity aeroacoustic tonal noise. Taking radiation damping as the core design parameter, a systematic sensitivity analysis was conducted on geometric modifications: aft door length, front door angle, cavity volume, and the introduction of a longitudinal gap. Key findings: shortening the aft door reduces the resonance peak by 8.5 dB; introducing a longitudinal gap with a 10% width reduces the Q-factor by approximately 50%; a combined control strategy (2.5% gap width and 6% cavity volume reduction) achieves 4.9 dB of noise attenuation. Finally, this study establishes a validated acoustic-damping control framework, providing quantitative design criteria and technical guidance for aeroacoustic noise control of NLG cavities. Full article

According to Polish law, it is prohibited to perform excavations or locate buildings closer than 50 m to an embankment. In order to obtain exemption from this ban, filtration and stability analysis of the embankments and excavation in flood conditions must be performed. This paper presents the results of a numerical investigation of a real case on the interactions between an excavation and an embankment. A transient flow model was used for filtration simulations, and the obtained pore pressure distributions automatically underwent stability analysis. The stability and filtration simulation results are presented. The safe design of an excavation support is proven. Changes in the values of the Stability Factor (SF) and stability loss mechanism (sliding surface location) during a flood are observed and discussed, with possible explanations given. A parametric study focused on the influence of the length and stiffness of the steel sheet pile wall on the embankment and excavation behavior. The relationship between wall length and the Stability Factor (SF) is strongly nonlinear and differs significantly between the various phases of flooding. Shortening of the wall may lead to either a decrease or increase in the bending moment. The main novelty of this work is the combination of excavation support and anti-flood embankment analysis, for which references are very limited. Also, the parametric study is considered novel, with no similar analyses being found in the literature. The problem of the reasonable selection of design values of the bending moment in the sheet pile wall is also often omitted. Additionally, one of the analyzed excavations is located on the waterside, where usually only excavations located on the airside are taken into account. All numerical simulations were performed using the ZSOIL.PC FEM (Finite Element Method) system. Full article

Weld root reinforcement is a critical geometric parameter governing stress concentration and structural performance in thin-walled stainless-steel piping systems designed to ASME B31.3. While current codes specify permissible dimensional limits, they do not explicitly quantify how incremental variations in root height influence stress distribution under realistic service loading conditions. This study integrates finite element analysis (FEA) with experimentally validated GTAW weld profiles to evaluate the structural influence of weld root height in 316L stainless-steel pipe joints. An experimentally manufactured 4 in schedule 10S joint with a measured root height of less than 1.5 mm was adopted as the baseline geometry. Additional models with reinforcement heights of 1.138, 2.0, 2.5, and 3.0 mm were evaluated under two representative load cases: (i) internal pressure combined with drag and axial thrust (LC-1), and (ii) internal pressure with thrust only (LC-2). The results demonstrate that reinforcement heights exceeding 2.0 mm increase von Mises, hoop, longitudinal, and radial stress gradients, with peak stresses shifting toward the weld toe under drag-inclusive loading. In contrast, reinforcement ≤2 mm provides smoother load transfer and reduced stiffness discontinuity across the weld interface. The combined numerical and experimental findings support a stress-informed upper limit of 2 mm for weld root reinforcement in thin-walled stainless-steel pipelines, offering a performance-based complement to existing dimensional acceptance criteria. Full article

Hydrogen embrittlement poses a recognized risk to the structural integrity of carbon steels used in maritime and hydrogen-related infrastructure. This study presents an experimental, numerical, and microstructural assessment of hydrogen embrittlement in ASTM A36 steel under four-point bending loading. Specimens with and without pre-existing notches were subjected to controlled cathodic hydrogen charging for exposure times up to 36 h to evaluate the combined effects of hydrogen diffusion and stress concentration. Experimental force–vertical displacement responses showed a progressive degradation of mechanical performance with increasing hydrogen exposure, characterized by reductions in yield force, ultimate force, and flexural stiffness, with more evident effects in notched specimens. Quantitative analysis indicated reductions of up to approximately 15% in yield force and 4% in flexural rigidity. Finite element models were developed to reproduce the experimental force–displacement behavior, showing good agreement and supporting the adopted numerical approach. Microstructural analysis by scanning electron microscopy revealed hydrogen-assisted damage mechanisms, including intergranular and transgranular microcracking, interfacial decohesion, hydrogen trapping at inclusions, and localized surface blistering near notch roots. The combined results indicate that hydrogen exposure leads to measurable reductions in stiffness and load-bearing capacity, particularly in the presence of geometric discontinuities. Full article

The load transfer method is important for the settlement prediction of axially loaded piles, but in multi-layered complex soils, it lacks analytical solutions. Traditional numerical methods such as the finite element method suffer from strong dependence on mesh generation, time-consuming iterative calculations, and high computational costs for back-analysis. This paper proposes a load transfer analysis model based on a Domain Decomposition Physics-Informed Neural Network. A multi-subnet parallel architecture is adopted to simulate multi-layered soils, solving the problem of inter-layer stress–strain discontinuity through interface coupling and gradient continuity constraints; a non-dimensionalization system and a hard constraint mechanism are introduced to enhance training efficiency and physical consistency; and a two-stage analysis framework comprising surrogate model forward analysis and field data inversion is established. Numerical experimental results indicate that the forward analysis of this model is in high agreement with FEM simulation results, and computational efficiency is improved by six orders of magnitude; based on a small amount of field static load test data, multi-layer soil parameters are accurately inverted, achieving more precise pile settlement prediction than FEM. Comparative analysis validates the effectiveness of the domain decomposition multi-subnet over a single network, demonstrating extensibility to hyperbolic and exponential multi-soil constitutive models. Full article

The hyperloop transportation system is a promising ultra-high-speed mobility solution operating in a reduced-pressure environment, where pod performance is governed by the coupled behaviour of structural integrity, aerodynamics, and electromagnetic propulsion. This paper presents the design, numerical analysis, and performance evaluation of a lightweight hyperloop pod equipped with a linear induction motor (LIM)-based propulsion and electromagnetic stabilisation system. The pod chassis was fabricated using Carbon Fibre-Reinforced Polymer (CFRP) and Aluminium 6061-T6, achieving a significant weight reduction while maintaining structural safety. Finite Element Analysis reveals a maximum von Mises stress of 82 MPa, which is well below the material yield strength, and a maximum deformation of 0.64 mm under worst-case loading conditions. Modal analysis indicates the first natural frequency at 47.6 Hz, ensuring sufficient separation from operational excitation frequencies. Computational Fluid Dynamics analysis conducted inside a rectangular tube shows a drag coefficient reduction of approximately 18% compared to a baseline blunt design, with stable velocity distribution and no flow choking at operating speeds. The optimised nose geometry enables rapid acceleration, achieving 25 km/h within 1.1 s in prototype testing. The LIM analysis demonstrates a peak thrust of 1.85 kN at an optimal slip range of 6–8%, with operating currents between 35 and 55A and power consumption of 18–25 kW. Thermal analysis confirms a maximum stator temperature of 78 °C, remaining within safe operating limits. The integrated numerical and experimental results confirm the feasibility, efficiency, and stability of the proposed hyperloop pod design. Full article

Steel jackets are widely used for the seismic retrofitting of reinforced concrete (RC) beam–column joints. However, the details and efficiencies of steel jackets are directly impacted by the presence of transverse beams. An in-depth understanding of this issue has been lacking so far. In this study, using realistic configurations of transverse beams, the seismic performance of exterior RC beam–column joints retrofitted according to the modified steel jacketing method were investigated numerically and theoretically. The refined nonlinear three-dimensional finite element approach was adopted and verified against experimental observations. A series of parameters were considered, including the number of transverse beams; the thickness, width and spacing of the steel strips at joint panels; and the axial compression ratio of columns. The results obtained from twenty specimens in terms of load response, cracking pattern, stress distribution, stiffness degradation and energy dissipation confirmed the effectiveness of the modified steel jacketing method. Significant differences among the roles of the parameters were revealed, and the reasons behind the differences were analyzed. Moreover, by means of significance analysis, the width and thickness of the steel strips were identified as the most influential parameters on the shear capacities of the joint panels with single- and double-sided transverse beams, respectively. Furthermore, based on the softened strut-and-tie model, a design approach for predicting the shear contribution of steel jackets in the presence of transverse beams was proposed for engineering applications. Full article

The long-term behavior of reinforced concrete (RC) structures under sustained loading is strongly affected by creep and cracking, particularly under service conditions where tension stiffening and curvature changes are significant. This study investigates the flexural response of cracked RC beams through combined numerical and experimental analyses. A new 1D finite element model is proposed, integrating nonlinear material behavior, damage mechanics, and time-dependent effects, including creep in both compression and tension. The model relies on a layered fiber section approach and uses a Newton–Raphson iterative procedure to solve equilibrium, allowing accurate prediction of strain, curvature, and internal force evolution over time. The model shows excellent agreement with experimental observations and ABAQUS simulations, accurately capturing deflection trends and crack development. Its performance is further validated using a database of 55 RC beams, including specimens with recycled aggregates and fiber reinforcement. Across this dataset, 84.5% of predicted deflections fall within ±1 mm of measured values, with an R² of 0.960, demonstrating strong reliability. A Sobol-based sensitivity analysis identifies load ratio as the most influential parameter on long-term deflection, followed by concrete strength and humidity. Overall, the model offers an efficient and robust tool for long-term deflection prediction, bridging simplified design rules and complex 3D simulations. Full article

Hatay (Ancient Antioch), one of Türkiye’s most historically significant and seismically active provinces, experienced extensive damage during the 6 February 2023 Kahramanmaraş earthquake sequence (Mw = 7.7 and Mw = 7.6) and its aftershocks. Among the affected structures, masonry mosques and minarets suffered critical damage, revealing significant seismic vulnerabilities. This study provides a comprehensive evaluation of the seismic performance and structural vulnerabilities of masonry mosques and minarets in Hatay following the devastating 2023 Kahramanmaraş earthquake sequence. By integrating extensive field observations with advanced numerical analysis, the research documents widespread damage to both traditional kiosk-style and classical minarets, identifying critical factors such as poor local soil conditions, insufficient material strength, and lack of engineering services that contributed to structural collapses, including that of the historic Habibi Neccar Mosque. Through finite element analysis (FEA) using ABAQUS, the study compares different material configurations to assess nonlinear dynamic responses under representative seismic excitations, revealing that recorded ground motions in Hatay significantly exceeded current design-level spectra. The findings offer vital insights for the seismic assessment, retrofitting, and preservation of irreplaceable cultural and religious heritage structures in seismically active regions. This study addresses the enhancement of seismic resistance to historical structures not merely as a safety issue, but also as a social sustainability element that ensures the transmission of cultural heritage to future generations. Full article