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Keywords = cutout shape

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19 pages, 12353 KiB  
Article
The Impact of the Core Laminate Shaping Process on the Parameters and Characteristics of the Synchronous Reluctance Motor with Flux Barriers in the Rotor
by Zbigniew Gmyrek
Energies 2025, 18(5), 1222; https://doi.org/10.3390/en18051222 - 2 Mar 2025
Cited by 1 | Viewed by 1008
Abstract
This article describes the findings of a study that examined the impact of the process of shaping the stator core of a synchronous reluctance motor on its operating parameters. The SynRM motor, with compact geometrical dimensions and a flux barrier rotor, was chosen [...] Read more.
This article describes the findings of a study that examined the impact of the process of shaping the stator core of a synchronous reluctance motor on its operating parameters. The SynRM motor, with compact geometrical dimensions and a flux barrier rotor, was chosen for this study, for which the technological process of forming the stator and rotor cores may be critical. The numerical results for three types of stator core structures were compared. The first, which is commonly used by academics, has no technological cutouts in the stator. The second type has cutouts for the clamps that hold the core laminates together. The third one has cutouts that allow the core to be positioned inside the motor housing. The research campaign also investigated the effect of partial material structure degradation caused by core laminate shaping on motor operation parameters. As a consequence of the computations, the characteristics and motor parameters were compared, including torque ripple, stator core loss, and motor efficiency. It has been demonstrated that, in the case of SynRM motors with relatively small geometric dimensions, technological cutouts caused by the shaping of stator core laminates can drastically influence the motor’s characteristics. Full article
(This article belongs to the Special Issue Design, Analysis, Optimization and Control of Electric Machines)
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13 pages, 14655 KiB  
Article
Biomechanical Evaluation of a Novel V-Shaped A2 Pulley Reconstruction Technique Using a Free Palmaris Longus Tendon Graft Tenodesis
by Gabriel Halát, Hannah E. Halát, Lukas L. Negrin, Thomas Koch, Lena Hirtler, Christoph Fuchssteiner and Stefan Hajdu
J. Clin. Med. 2025, 14(4), 1092; https://doi.org/10.3390/jcm14041092 - 8 Feb 2025
Viewed by 872
Abstract
Background: The aim of this biomechanical investigation was to evaluate a V-shaped three-point graft tenodesis technique using a free palmaris longus (PL) tendon for reconstructing traumatic A2 pulley lesions and to compare its biomechanical performance with two previously described reconstruction techniques. Methods [...] Read more.
Background: The aim of this biomechanical investigation was to evaluate a V-shaped three-point graft tenodesis technique using a free palmaris longus (PL) tendon for reconstructing traumatic A2 pulley lesions and to compare its biomechanical performance with two previously described reconstruction techniques. Methods: After A2 pulley lesion simulation in 27 fingers (index, middle and ring finger) from nine human anatomical hand specimens, reconstructions were performed using the innovative V-shaped graft tenodesis technique, a double-loop encircling technique and a suture anchor graft fixation technique. Load at failure and the failure mechanisms were evaluated. Results: The V-shaped graft tenodesis technique was superior biomechanically (p = 0.004) considering load at failure (mean: 299 N). The only observed failure mechanism in this group was the extrusion of the central tenodesis screw. In contrast, reconstructions in the other two groups failed due to suture cut-out. Conclusions: Patients may benefit from the new technique’s high load tolerance during early mobilization. Furthermore, a reduction in complications may be anticipated due to an absence of sutures and the sparing of extensor structures. Full article
(This article belongs to the Special Issue Innovation in Hand Surgery)
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20 pages, 9846 KiB  
Article
Design and Testing of a Pleurotus pulmonarius Stick Cutting Machine
by Chunlin Cai, Pengyu Jing, Lihong Wang, Qi Niu, Haobo Jiao, Chen Ma and Chengsong Li
Agriculture 2024, 14(10), 1795; https://doi.org/10.3390/agriculture14101795 - 12 Oct 2024
Viewed by 1040
Abstract
Based on the cultivation environment and material parameters of Pleurotus pulmonarius sticks, a P. pulmonarius stick cutting machine is designed to solve the problem of directly realizing the cutting of P. pulmonarius sticks for a net-shaped mushroom stick cultivation layer frame. The machine [...] Read more.
Based on the cultivation environment and material parameters of Pleurotus pulmonarius sticks, a P. pulmonarius stick cutting machine is designed to solve the problem of directly realizing the cutting of P. pulmonarius sticks for a net-shaped mushroom stick cultivation layer frame. The machine consists of three parts: a traveling trolley, an XYZ three-axis moving mechanism, and a clamping and cutting mechanism. Based on the force analysis of the clamping and cutting mechanism and the P. pulmonarius sticks, the key components were designed and selected. A prototype was constructed, and several cutting tests were conducted, with the cutting speed, number of cutting circles, and depth of the cut as the main factors. The success rate of cutting, the roundness of the cut, and the degree of loss in terms of the cutout substrate, were used as the performance indicators. An optimized design, based on orthogonal testing, was employed to determine the optimal parameter combinations for the cutting process. The optimal parameters were found to be a cutting speed of 376.3 r/min, 5.4 cutting circles, and a cutting depth of 4 mm. Finally, a validation test was carried out on the machine, and the results show that under the same parameter conditions, the success rate of cutting was 86.6%, the roundness of the cut was 0.235, and the degree of loss in terms of the cutout substrate was 0.851%, which is consistent with the optimization results. This study provides a reference, including a practical reference, for the design and development of a machine to realize the cutting of P. pulmonarius sticks for a cultivation layer frame. Full article
(This article belongs to the Section Agricultural Technology)
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19 pages, 9835 KiB  
Article
Buckling Performance Evaluation of Double-Double Laminates with Cutouts Using Artificial Neural Network and Genetic Algorithm
by Ruiqing Ju, Kai Zhao, Carol A. Featherston and Xiaoyang Liu
Materials 2024, 17(19), 4677; https://doi.org/10.3390/ma17194677 - 24 Sep 2024
Viewed by 1274
Abstract
Although the double-double (DD) laminates proposed by Tsai provide a promising option for achieving better structural performance with lower manufacturing and maintenance costs, the buckling performance of perforated DD laminates still remains clear. In this study, optimal ply angles, rotation angles, and the [...] Read more.
Although the double-double (DD) laminates proposed by Tsai provide a promising option for achieving better structural performance with lower manufacturing and maintenance costs, the buckling performance of perforated DD laminates still remains clear. In this study, optimal ply angles, rotation angles, and the corresponding maximum buckling loads are determined for DD laminates with various cutouts, which are used for comparisons to evaluate the effects of cutout size and shape on the buckling behaviour of perforated DD laminates. Apart from conventional circular and elliptical cutouts, the use of a combined-shape cutout for DD laminates is also investigated. As a large number of optimisations are required to obtain the maximum buckling loads for different cases in this study, an efficient optimisation method for perforated DD laminates is proposed based on an artificial neural network (ANN) and a genetic algorithm (GA). Unlike conventional quadaxial (QUAD) laminates, the repetition of a four-ply sublaminate in DD laminates makes their layup to be represented by only two ply angles; hence, the application of ANN models for predicting the buckling behaviour of various perforated DD laminates is studied in this paper. The superior performance of the ANN models is demonstrated by comparisons with other machine learning models. Instead of using the time-consuming FEA, the developed ANN model is utilised within a GA to obtain the maximum buckling load of perforated DD laminates. Compared to the circular cutout, the use of elliptical and combined-shape cutouts leads to more noticeable changes in the optimal ply angles as the cutout size increases. Based on the obtained results, the use of the combined-shape cutout is recommended for DD laminates. Full article
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20 pages, 17511 KiB  
Article
Perforated and Composite Beam and Arch Design Optimization during Asymmetric Post-Buckling Deformation
by Igor Andrianov, Viktor Olevskyi, Oleksandr Olevskyi and Yuliia Olevska
Symmetry 2024, 16(8), 1050; https://doi.org/10.3390/sym16081050 - 15 Aug 2024
Viewed by 1314
Abstract
The structural elements of buildings have recently required the development of efficient design solutions due to increased dynamic and thermal loads. The main solution for improving the efficiency of such elements involves creating lightweight non-uniform beam and arch structures from alloyed steel, which [...] Read more.
The structural elements of buildings have recently required the development of efficient design solutions due to increased dynamic and thermal loads. The main solution for improving the efficiency of such elements involves creating lightweight non-uniform beam and arch structures from alloyed steel, which has better mechanical characteristics. The most promising approach is the use of welded beams and arches with perforated partitions and composite beams, which are often used together, for instance, as structural elements of cylindrical shells. The development of an effective cross-sectional shape for perforated beams and crane girders is considered, taking into account the strength, local stability, resistance to flat bending, and fatigue deformation. It has been shown that the effective form for perforated beams is a box-shaped structure made of perforated shvellers. Calculations for selecting a rational design from the assortment of hot-rolled shveller profiles have demonstrated that a significant reduction in the weight of the structure can be achieved by using the proposed cross-sectional shape. An evaluation of the fatigue strength of composite metal crane girders operating in harsh conditions has shown the effectiveness of using hot-rolled I-beams as their upper flange, as well as the necessity of using hot-rolled I-beams to ensure strength in their lower part. When choosing the rational parameters of an arch design, multiple recalculations of its bending with respect to technological cutouts in the thickness are necessary; hence, simplified calculation schemes are commonly used. Some authors simplify this process by replacing an arch with a cutout with a solid arch reduced in height by the cutout radius. We have shown that this model does not accurately describe the actual distribution of forces and displacements, leading to inadequate results. We have developed a simplified methodology for the preliminary calculation of a circular arch with a cutout, which includes correction coefficients calculated by us. A calculation of the flat stress–strain state of an elastic circular metal arch with a central semicircular cutout under various ratios of design parameters and uniform external pressure was conducted. A dependence of the stress concentration coefficient at the cutout’s apex on the ratio of the cutout radius and arch thickness was obtained. These results can be generalized for reinforced non-uniform shells and for the fuzzy application of external influences. Full article
(This article belongs to the Section Physics)
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15 pages, 9215 KiB  
Article
Selection of Appropriate Criteria for Optimization of Ventilation Element for Protective Clothing Using a Numerical Approach
by Sanjay Rajni Vejanand, Alexander Janushevskis and Ivo Vaicis
Computation 2024, 12(5), 90; https://doi.org/10.3390/computation12050090 - 2 May 2024
Viewed by 1592
Abstract
While there are multiple methods to ventilate protective clothing, there is still room for improvement. In our research, we are using ventilation elements that are positioned at the ventilation holes in the air space between the body and clothing. These ventilation elements allow [...] Read more.
While there are multiple methods to ventilate protective clothing, there is still room for improvement. In our research, we are using ventilation elements that are positioned at the ventilation holes in the air space between the body and clothing. These ventilation elements allow air to flow freely while preventing sun radiation, rain drops, and insects from directly accessing the body. Therefore, the shape of the ventilation element is crucial. This led us to study the shape optimization of ventilation elements through the utilization of metamodels and numerical approaches. In order to accomplish the objective, it is crucial to thoroughly evaluate and choose suitable criteria for the optimization process. We know from prior research that the toroidal cut-out shape element provides better results. In a previous study, we optimized the shape of this element based on the minimum pressure difference as a criterion. In this study, we are using different criteria for the shape optimization of ventilation elements to determine which are most effective. This study involves a metamodeling strategy that utilizes local and global approximations with different order polynomials, as well as Kriging approximations, for the purpose of optimizing the geometry of ventilation elements. The goal was achieved by a sequential process. (1) Planning the position of control points of Non-Uniform Rational B-Splines (NURBS) in order to generate elements with a smooth shape. (2) Constructing geometric CAD models based on the design of experiments. (3) Compute detailed model solutions using SolidWorks Flow Simulation. (4) Developing metamodels for responses using computer experiments. (5) Optimization of element shape using metamodels. The procedure is repeated for six criteria, and subsequently, the results are compared to determine the most efficient criteria for optimizing the design of the ventilation element. Full article
(This article belongs to the Section Computational Engineering)
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13 pages, 8192 KiB  
Article
Geometrically Non-Linear Plane Elasticity Problem in the Area of an Angular Boundary Cut-Out
by Lyudmila Frishter
Axioms 2023, 12(11), 1030; https://doi.org/10.3390/axioms12111030 - 2 Nov 2023
Cited by 1 | Viewed by 1297
Abstract
A relevant problem in the development and improvement of numeric analytical methods for the research of structures, buildings and construction is studying the stress–strain state of structures and construction with boundaries that have complex shapes. Deformations and stresses arise in a domain with [...] Read more.
A relevant problem in the development and improvement of numeric analytical methods for the research of structures, buildings and construction is studying the stress–strain state of structures and construction with boundaries that have complex shapes. Deformations and stresses arise in a domain with a geometrically non-linear shape of the boundary (cut-outs and cuts). These stresses and deformations have great values and gradients. Experiments carried out using the photoelasticity method show a change in the deformation order ratios for different subareas of the boundary cut-out area depending on proximity to the apex of the angular cut-out. Areas with minor deformations are observed, and areas where linear deformations and shears are more significant than rotations are also observed. In addition, areas where section rotations are more significant than linear and shear deformations are observed. According to the experimental data, the mathematical model of the SSS in the area of the apex of the cut-out of the domain boundary should take into account non-linear deformations. Hence, it is necessary to formulate the boundary value problem of the theory of elasticity, taking into account the geometrical non-linearity. The research aim of this paper is to formulate the problem of the elasticity theory taking into account the geometrical non-linearity in furtherance of the proposed mathematical model justified by the experimental data obtained using the photoelasticity method. The obtained formulation of the elasticity theory problem allows analyzing the form of the system of equations of the boundary value problem depending on the proximity of the considered area to the irregular point of the boundary, i.e., taking into account the difference in the effect of linear and shear deformations, rotations and forced deformations on the solution to the geometrically non-linear elastic problem dealing with forced deformations in the area of an angular cut-out of the boundary of the plane domain. Full article
(This article belongs to the Special Issue Applied Numerical Analysis in Civil Engineering)
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15 pages, 813 KiB  
Article
Minor and Major Strain: Equations of Equilibrium of a Plane Domain with an Angular Cutout in the Boundary
by Lyudmila Frishter
Axioms 2023, 12(9), 893; https://doi.org/10.3390/axioms12090893 - 19 Sep 2023
Viewed by 1591
Abstract
Large values and gradients of stress and strain, triggering concentrated stress and strain, arise in angular areas of a structure. The strain action, leading to the finite loss of contact between structural elements, also triggers concentrated stress. The loss of contact reaches an [...] Read more.
Large values and gradients of stress and strain, triggering concentrated stress and strain, arise in angular areas of a structure. The strain action, leading to the finite loss of contact between structural elements, also triggers concentrated stress. The loss of contact reaches an irregular point and a line on the boundary. The theoretical analysis of the stress–strain state (SSS) of areas with angular cutouts in the boundary under the action of discontinuous strain is reduced to the study of singular solutions to the homogeneous problem of elasticity theory with power-related features. The calculation of stress concentration coefficients in the domain of a singular solution to the elastic problem makes no sense. It is experimentally proven that the area located near the vertex of an angular cutout in the boundary features substantial strain and rotations, and it corresponds to higher values of the first and second derivatives of displacements along the radius in cases of sufficiently small radii in the neighborhood of an irregular boundary point. As far as these areas are concerned, it is necessary to consider the plane problem of the elasticity theory, taking into account the geometric nonlinearity under the action of strain, to analyze the effect of relationships between strain orders, rotations, and strain on the form of the equation of equilibrium. The purpose of this work is to analyze the effect of relationships between strain orders, rotations, and strain on the form of the equilibrium equation in the polar system of coordinates for a V-shaped area under the action of temperature-induced strain, taking into account geometric non-linearity and physical linearity. Full article
(This article belongs to the Special Issue Applied Numerical Analysis in Civil Engineering)
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19 pages, 6298 KiB  
Article
Correction of Shape Error at Cut-In and Cut-Out Points in Abrasive Waterjet Cutting of Carbon Fiber Reinforced Polymer (CFRP)
by Ioan Alexandru Popan, Cosmin Cosma, Alina Ioana Popan, Nicolae Panc, Daniel Filip and Nicolae Balc
Machines 2023, 11(8), 800; https://doi.org/10.3390/machines11080800 - 3 Aug 2023
Cited by 6 | Viewed by 1867
Abstract
This paper presents a solution aimed at enhancing the accuracy of abrasive waterjet cutting (AWJC) for the processing of carbon-fiber-reinforced polymers (CFRP). Processing CFRP with high accuracy and good surface quality in a short processing time is a difficult task. One crucial problem [...] Read more.
This paper presents a solution aimed at enhancing the accuracy of abrasive waterjet cutting (AWJC) for the processing of carbon-fiber-reinforced polymers (CFRP). Processing CFRP with high accuracy and good surface quality in a short processing time is a difficult task. One crucial problem is the occurrence of shape errors, overcuts, at the cut-in and cut-out point during the cutting process. Shape errors have the potential to create mechanical stress concentrators, which can result in structural failures and compromise the integrity and reliability of components. The primary objective of this study was to gain a comprehensive understanding of the formation mechanism underlying the shape error. The observed shape error is closely associated with both the lead-in/lead-out strategies employed and the process parameters selected. The experimental investigation focused on two commonly used strategies for CFRP cutting: lead-in/lead-out in arc and lead-in/lead-out in line. In order to minimize shape errors, this study proposed a correction method that offers a set of recommendations for selecting the appropriate lead-in/out strategy and a suitable combination of process parameters. Additionally, a mathematical model has been developed to determine the depth of the shape error. The conclusions drawn from this study have been successfully validated through industrial applications. Full article
(This article belongs to the Special Issue Advances in Computer-Aided Technology II)
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12 pages, 4583 KiB  
Article
Stability Analysis of Thin-Walled Perforated Composite Columns Using Finite Element Method
by Katarzyna Falkowicz
Materials 2022, 15(24), 8919; https://doi.org/10.3390/ma15248919 - 13 Dec 2022
Cited by 8 | Viewed by 1813
Abstract
Open holes or cut-outs have been commonly used in composite structures for various engineering purposes. Those elements often demand perforation especially for weight reduction and to ease maintenance and servicing operations, for example, in aircraft wing ribs. This work presents a numerical study [...] Read more.
Open holes or cut-outs have been commonly used in composite structures for various engineering purposes. Those elements often demand perforation especially for weight reduction and to ease maintenance and servicing operations, for example, in aircraft wing ribs. This work presents a numerical study of the stability behavior of composite perforated columns subjected to a compressive load. Profiles were made of CFRP laminate and weakened by three types of cut-out. Four parameters, spacing ratio S/D0, opening ratio D/D0, hole shape and arrangement of layers, were selected to check their effect on the buckling load and postbuckling behavior of the tested channel profiles. To carry out the numerical analysis, the Abaqus software was used. The results obtained during the analysis helped to identify the best combination of tested parameters to obtain the highest critical load. The performed analysis show that the columns’ behavior is sensitive to configuration of composite, opening ratio and hole shape. Full article
(This article belongs to the Special Issue Compressive Behavior of Materials and Structures)
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15 pages, 5047 KiB  
Article
Design of Reservoirs Enabling Stress-Induced Sequential Release Systems
by Osamah Altabal, Christian Wischke and Andreas Lendlein
Pharmaceutics 2022, 14(12), 2611; https://doi.org/10.3390/pharmaceutics14122611 - 26 Nov 2022
Viewed by 1644
Abstract
Mechanical stress is recognized as a principle for opening enclosed compartments through compression, stretching, or shear, eventually resulting in the onset of a diffusion-controlled release. Here, we hypothesized that the geometrical design of cavities (cut-outs) introduced as containers in elastic polymer substrates and [...] Read more.
Mechanical stress is recognized as a principle for opening enclosed compartments through compression, stretching, or shear, eventually resulting in the onset of a diffusion-controlled release. Here, we hypothesized that the geometrical design of cavities (cut-outs) introduced as containers in elastic polymer substrates and sealed with a brittle coating layer would enable a pre-defined release of different compounds by stress concentration phenomena. Design criteria such as cut-out shapes, orientations, and depths were initially assessed for suitably different stress concentrations in computational models. In substrates fabricated from polydimethylsiloxane by photolithographic techniques, the local strains at horizontal rectangular, circular, and vertical rhombus-shaped cut-outs systematically increased under horizontal stretching as proposed. When filled with model compounds and coated with poly(n-butyl cyanoacrylate), a pre-defined induced breakage of the coating and compound release was confirmed upon continuous uniaxial stretching. This proof of concept demonstrates how device design and functions interlink and may motivate further exploration in technology and medicine for deformation-induced on-demand dosage applications. Full article
(This article belongs to the Section Pharmaceutical Technology, Manufacturing and Devices)
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20 pages, 3911 KiB  
Article
Finite Element Analysis of Axially Loaded RC Walls with Openings Strengthened Using Textile Reinforced Mortar for Sustainable Structures
by Mohannad Alhusban and Azadeh Parvin
Buildings 2022, 12(11), 1993; https://doi.org/10.3390/buildings12111993 - 16 Nov 2022
Cited by 2 | Viewed by 2711
Abstract
Sustainable solutions in the building construction industry promotes the use of innovative materials such as textile reinforced mortar (TRM) as a strengthening technique resulting in a reduced life-cycle cost. This paper presents a nonlinear finite element analysis (FEA) of TRM strengthened RC walls [...] Read more.
Sustainable solutions in the building construction industry promotes the use of innovative materials such as textile reinforced mortar (TRM) as a strengthening technique resulting in a reduced life-cycle cost. This paper presents a nonlinear finite element analysis (FEA) of TRM strengthened RC walls with cut-out openings under axial loading. FEA models were developed and validated with two experimental tests from the literature. Subsequently, a parametric study was performed to investigate the contribution of TRM in strengthening RC walls considering various opening sizes, types, numbers and orientations of window openings, and TRM strengthening configurations. The parametric study results revealed that strengthened models with smaller opening sizes had higher axial strength enhancement. Furthermore, the increase in the axial load capacities of walls with door and window openings were 34 and 26%, respectively, as compared to the corresponding control ones. TRM was more effective with a lower opening aspect ratio (Ho/Lo). In addition, confining the wall piers with U-shaped TRM jackets was the most effective configuration in improving the walls’ axial strengths with maximum enhancements of 16 and 22% as compared to the models strengthened with side-bonded sheets and strips, respectively. Finally, the axial strengths of the FEA models were also compared with the existing empirical solution and showed reasonable correlation with an average discrepancy of 15%. Full article
(This article belongs to the Special Issue The Impact of Building Materials on Construction Sustainability)
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25 pages, 13125 KiB  
Article
Part Affinity Fields and CoordConv for Detecting Landmarks of Lumbar Vertebrae and Sacrum in X-ray Images
by Chang-Hyeon An, Jeong-Sik Lee, Jun-Su Jang and Hyun-Chul Choi
Sensors 2022, 22(22), 8628; https://doi.org/10.3390/s22228628 - 9 Nov 2022
Cited by 7 | Viewed by 4558
Abstract
With the prevalence of degenerative diseases due to the increase in the aging population, we have encountered many spine-related disorders. Since the spine is a crucial part of the body, fast and accurate diagnosis is critically important. Generally, clinicians use X-ray images to [...] Read more.
With the prevalence of degenerative diseases due to the increase in the aging population, we have encountered many spine-related disorders. Since the spine is a crucial part of the body, fast and accurate diagnosis is critically important. Generally, clinicians use X-ray images to diagnose the spine, but X-ray images are commonly occluded by the shadows of some bones, making it hard to identify the whole spine. Therefore, recently, various deep-learning-based spinal X-ray image analysis approaches have been proposed to help diagnose the spine. However, these approaches did not consider the characteristics of frequent occlusion in the X-ray image and the properties of the vertebra shape. Therefore, based on the X-ray image properties and vertebra shape, we present a novel landmark detection network specialized in lumbar X-ray images. The proposed network consists of two stages: The first step detects the centers of the lumbar vertebrae and the upper end plate of the first sacral vertebra (S1), and the second step detects the four corner points of each lumbar vertebra and two corner points of S1 from the image obtained in the first step. We used random spine cutout augmentation in the first step to robustify the network against the commonly obscured X-ray images. Furthermore, in the second step, we used CoordConv to make the network recognize the location distribution of landmarks and part affinity fields to understand the morphological features of the vertebrae, resulting in more accurate landmark detection. The proposed network was evaluated using 304 X-ray images, and it achieved 98.02% accuracy in center detection and 8.34% relative distance error in corner detection. This indicates that our network can detect spinal landmarks reliably enough to support radiologists in analyzing the lumbar X-ray images. Full article
(This article belongs to the Special Issue Advances of Deep Learning in Medical Image Interpretation)
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16 pages, 6525 KiB  
Article
Numerical Investigations of Perforated CFRP Z-Cross-Section Profiles, under Axial Compression
by Katarzyna Falkowicz
Materials 2022, 15(19), 6874; https://doi.org/10.3390/ma15196874 - 3 Oct 2022
Cited by 18 | Viewed by 2016
Abstract
Thin-walled elements, thanks to their good properties, are increasingly used in structural applications, especially in the aircraft and building industries. These kinds of structures are often perforated for reducing weight and to ease servicing and maintenance operations, e.g., in aircraft wing ribs. These [...] Read more.
Thin-walled elements, thanks to their good properties, are increasingly used in structural applications, especially in the aircraft and building industries. These kinds of structures are often perforated for reducing weight and to ease servicing and maintenance operations, e.g., in aircraft wing ribs. These perforations cause a redistribution of stresses in the element which may change the ultimate strength of the structure and their elastic stiffness. The buckling behaviour of structural members with perforations is significantly influenced by the size, location, shape and number of perforations. Therefore, it is necessary to investigate the influence of these kinds of cut-out parameters on thin-walled structure buckling and postbuckling behaviour. This study investigated numerically the buckling and postbuckling behaviour of thin-walled perforated composite profiles with a Z-cross-section subjected to compression load. Numerical calculations were performed using the finite element method in the ABAQUS® program. The study investigated the effect of localisation and geometric parameters of cut-outs on the buckling load, postbuckling equilibrium path and failure load. Moreover, the perforated profiles were compared with a profile without cut-outs, which were experimentally tested in previous research. Results showed that the perforated profiles with a Z-cross-section do not lose their stability in the post-critical range. What is more, a well-chosen arrangement of the holes may prevent the mechanical properties from deteriorating. Full article
(This article belongs to the Special Issue Computational and Experimental Mechanics of Thin-Walled Structures)
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31 pages, 19378 KiB  
Article
Buckling Analysis of a Thin-Walled Structure Using Finite Element Method and Design of Experiments
by Mohamad Norfaieqwan Bin Kamarudin, Jaffar Syed Mohamed Ali, Abdul Aabid and Yasser E. Ibrahim
Aerospace 2022, 9(10), 541; https://doi.org/10.3390/aerospace9100541 - 23 Sep 2022
Cited by 32 | Viewed by 9799
Abstract
In structural engineering, thin-walled structures play an important role in the design of the lightweight structural model. It carries different loading conditions when it exists in any model, and it is designed with thin plates or thin shells. Penetrating thin-walled structures with different [...] Read more.
In structural engineering, thin-walled structures play an important role in the design of the lightweight structural model. It carries different loading conditions when it exists in any model, and it is designed with thin plates or thin shells. Penetrating thin-walled structures with different kinds of holes can decrease their weight and facilitate repair and maintenance operations, such as those carried out for the wing of an airplane. In such applications, cutouts are often employed as part of the design of composite plates. Therefore, this paper attempted to design and analyse the thin-walled composite structure with a C-cross-section shape. To model and analyse the structures, a finite element method was utilized using the ABAQUS commercial tool, and the results of critical buckling load for different laminate types were obtained. Composite materials and structures have different parameters that can vary the results of analysis; therefore, to optimize the current mode a design of experiments method is used via MINITAB 20 and Design-Expert 13 tools. The selected parameters for this work were the opening ratio, spacing ratio, and shape of the hole for the output response as a critical buckling load was carried out. Based on the current results of simulation and optimization, it was found that the parameters of composite materials and structures will impact the output response, and the current study investigated the optimum parameters for the best possible outcome of the structural analysis. Full article
(This article belongs to the Special Issue Recent Advances in Technologies for Aerospace Maintenance)
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