Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.035
Jan Kec , Lukáš Jeníček , Jakub Jindra , Martin Šperl , Lubomír Gajdoš , Jan Bejdl , Klára Kuchťáková , Tomáš Prošek
The paper deals with the testing of fatigue crack growth rate (FCGR) and fracture toughness (FT) of electrochemically hydrogen-charged HFW welds of X52 steel. The FCGR tests revealed a significantly accelerated crack growth rate in the presence of hydrogen, particularly at low ΔK values. This effect gradually decreased at higher ΔK levels, likely due to electrolyte depletion. The fracture surfaces of samples at ΔK = 20 MPa.m0.5 show ductile striation patterns in samples tested in air; on the other hand, samples tested in hydrogen show mixed fractures with quasi-cleavage facets and indistinct striation patterns. In FT testing, hydrogen caused a notable reduction in the J0.2 parameter (43 %). The samples tested in air consistently exceeded 200 kJ/m²; hydrogen charged samples mostly fell below this threshold, with one case even dropping under 100 kJ/m². Fractography analysis confirmed a micro-void coalescence mechanism in air and quasi-cleavage facets with localized dimple areas under hydrogen charging.
{"title":"Fatigue crack growth rate and fracture toughness of electrochemically hydrogen-charged HFW welds of X52 steel","authors":"Jan Kec , Lukáš Jeníček , Jakub Jindra , Martin Šperl , Lubomír Gajdoš , Jan Bejdl , Klára Kuchťáková , Tomáš Prošek","doi":"10.1016/j.prostr.2026.01.035","DOIUrl":"10.1016/j.prostr.2026.01.035","url":null,"abstract":"<div><div>The paper deals with the testing of fatigue crack growth rate (FCGR) and fracture toughness (FT) of electrochemically hydrogen-charged HFW welds of X52 steel. The FCGR tests revealed a significantly accelerated crack growth rate in the presence of hydrogen, particularly at low ΔK values. This effect gradually decreased at higher ΔK levels, likely due to electrolyte depletion. The fracture surfaces of samples at ΔK = 20 MPa.m<sup>0.5</sup> show ductile striation patterns in samples tested in air; on the other hand, samples tested in hydrogen show mixed fractures with quasi-cleavage facets and indistinct striation patterns. In FT testing, hydrogen caused a notable reduction in the J<sub>0.2</sub> parameter (43 %). The samples tested in air consistently exceeded 200 kJ/m²; hydrogen charged samples mostly fell below this threshold, with one case even dropping under 100 kJ/m². Fractography analysis confirmed a micro-void coalescence mechanism in air and quasi-cleavage facets with localized dimple areas under hydrogen charging.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"77 ","pages":"Pages 264-271"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.029
Fang Liu , Daniel T.P. Fong , Simin Li
The mechanical interaction at the limb–socket interface is a critical determinant of user comfort and skin integrity; however, the specific contributions of the coefficient of friction (μ) and Poisson’s ratio (ν) have not been quantitatively established. Objective: The objective of this work is to evaluate how μ modulates stresses in the residual limb and its potential association with socket safety, and to determine how ν governs socket maximum stress and structural safety margins. Methods: Above-knee finite-element (FE) model (elastic-plastic socket/base, first-order Ogden limb, rigid femur; C3D4H mesh) with parametric sweeps of μ (0.30–1.00) and ν (0.10–0.49) across polyethylene (PE), polyethylene terephthalate glycol (PETG), and high-performance carbon-fiber-reinforced polymers (HCFRPs). Results: Residual limb soft-tissue maximum Von Mises stress showed a U-shaped dependence on μ with a minimum near 0.7; the socket stress-to-yield ratio was largely insensitive to μ but differed by material (largest margin for HCFRPs, intermediate for PETG, smallest for PE). Increasing ν reduced socket maximum Von Mises stress by ~16–18% from 0.10 to 0.50 for all materials, with the ranking of safety margins (HCFRPs > PETG > PE) consistent with that observed in the μ analysis. Conclusions: Specifying a mid-range μ (~0.7) together with socket materials of higher ν (0.40–0.50) constitutes an effective strategy to reduce soft-tissue stresses while preserving structural safety, thereby offering biomechanical criteria for liner selection and material specification.
{"title":"Balancing comfort and safety in transfemoral prosthetic sockets through finite-element modelling of interface mechanics","authors":"Fang Liu , Daniel T.P. Fong , Simin Li","doi":"10.1016/j.prostr.2026.01.029","DOIUrl":"10.1016/j.prostr.2026.01.029","url":null,"abstract":"<div><div>The mechanical interaction at the limb–socket interface is a critical determinant of user comfort and skin integrity; however, the specific contributions of the coefficient of friction (μ) and Poisson’s ratio (ν) have not been quantitatively established. Objective: The objective of this work is to evaluate how μ modulates stresses in the residual limb and its potential association with socket safety, and to determine how ν governs socket maximum stress and structural safety margins. Methods: Above-knee finite-element (FE) model (elastic-plastic socket/base, first-order Ogden limb, rigid femur; C3D4H mesh) with parametric sweeps of μ (0.30–1.00) and ν (0.10–0.49) across polyethylene (PE), polyethylene terephthalate glycol (PETG), and high-performance carbon-fiber-reinforced polymers (HCFRPs). Results: Residual limb soft-tissue maximum Von Mises stress showed a U-shaped dependence on μ with a minimum near 0.7; the socket stress-to-yield ratio was largely insensitive to μ but differed by material (largest margin for HCFRPs, intermediate for PETG, smallest for PE). Increasing ν reduced socket maximum Von Mises stress by ~16–18% from 0.10 to 0.50 for all materials, with the ranking of safety margins (HCFRPs > PETG > PE) consistent with that observed in the μ analysis. Conclusions: Specifying a mid-range μ (~0.7) together with socket materials of higher ν (0.40–0.50) constitutes an effective strategy to reduce soft-tissue stresses while preserving structural safety, thereby offering biomechanical criteria for liner selection and material specification.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"77 ","pages":"Pages 215-220"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A novel method to predict the fracture-mechanical fatigue limit based on simulated cyclic resistance curves is presented. Plasticity-induced crack closure development, whose role in the fatigue limit analysis is emphasized due to its fast saturation, is modeled for short cracks under near-threshold loading via finite element analysis. Combined with the intrinsic threshold, the cyclic R-curve can be derived from the simulated crack closure response. The fatigue limit from crack arrest is determined by the tangency condition between nominal crack driving force and the cyclic R-curve. The fatigue limits predicted as a demonstration of the method are consistent with literature knowledge. The method can be employed to any geometry, material, crack, or loading configuration.
{"title":"Fatigue limit prediction with simulated cyclic resistance curves","authors":"Kimmo Kärkkäinen , Joona Vaara , Miikka Väntänen , Saana Bergman , Bernd Schönbauer , Tero Frondelius","doi":"10.1016/j.prostr.2025.12.281","DOIUrl":"10.1016/j.prostr.2025.12.281","url":null,"abstract":"<div><div>A novel method to predict the fracture-mechanical fatigue limit based on simulated cyclic resistance curves is presented. Plasticity-induced crack closure development, whose role in the fatigue limit analysis is emphasized due to its fast saturation, is modeled for short cracks under near-threshold loading via finite element analysis. Combined with the intrinsic threshold, the cyclic R-curve can be derived from the simulated crack closure response. The fatigue limit from crack arrest is determined by the tangency condition between nominal crack driving force and the cyclic R-curve. The fatigue limits predicted as a demonstration of the method are consistent with literature knowledge. The method can be employed to any geometry, material, crack, or loading configuration.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"76 ","pages":"Pages 11-18"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2025.12.282
D. Kaschube , M. Malekan , B. Bohlmann
This study investigates the influence of mean strain on the total number of cycles until failure of Ti6Al4V specimens manufactured using the cold metal fusion additive manufacturing method. In this innovative production technology, metal particles are coated with a polymer binder and joined together layer by layer using a powder bed printer designed for plastics by melting the polymer locally with a low-energy laser. The resulting green part is depowdered, de-bindered and sintered to achieve its full density. The fatigue performance is influenced by the surface roughness, inherent defects and the microstructure. This study investigates the influence of mean strain on the fatigue strength and which existing mean strain corrections can be used to predict the fatigue life of parts manufactured using this novel manufacturing technology.
{"title":"Mean Strain Influence in Low Cycle Fatigue Behavior of Ti6Al4V Additively Manufactured using Cold Metal Fusion","authors":"D. Kaschube , M. Malekan , B. Bohlmann","doi":"10.1016/j.prostr.2025.12.282","DOIUrl":"10.1016/j.prostr.2025.12.282","url":null,"abstract":"<div><div>This study investigates the influence of mean strain on the total number of cycles until failure of Ti6Al4V specimens manufactured using the cold metal fusion additive manufacturing method. In this innovative production technology, metal particles are coated with a polymer binder and joined together layer by layer using a powder bed printer designed for plastics by melting the polymer locally with a low-energy laser. The resulting green part is depowdered, de-bindered and sintered to achieve its full density. The fatigue performance is influenced by the surface roughness, inherent defects and the microstructure. This study investigates the influence of mean strain on the fatigue strength and which existing mean strain corrections can be used to predict the fatigue life of parts manufactured using this novel manufacturing technology.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"76 ","pages":"Pages 19-26"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Additive Manufacturing (AM) has rapidly advanced in the motorsport field, enabling the production of custom lightweight components with high-performance alloys. Rapid design iterations and short production lead times make AM ideal to improve component performance. However, predicting fatigue resistance remains challenging due to the inherent presence of manufacturing defects. This work presents the application of a defect-tolerant methodology to predict the impact of manufacturing defects on component performance under operating conditions. First, the manufacturing defects of standard fatigue specimens and a selected component were revealed by X-ray Computed Tomography. Then, machine learning-assisted Extreme Value Statistics was adopted to estimate the occurrence of different defect types in critical regions of the component. Finally, a probabilistic fracture-based design model was applied to quantify the influence of defect size on fatigue performance.
{"title":"Experience of defect tolerant design for Additively Manufactured components in high performance cars","authors":"Matteo Sepati , Giuliano Minerva , Luca Patriarca , Andrea Vignoni , Elia Sbettega , Massimo Giannozzi , Stefano Beretta","doi":"10.1016/j.prostr.2025.12.297","DOIUrl":"10.1016/j.prostr.2025.12.297","url":null,"abstract":"<div><div>Additive Manufacturing (AM) has rapidly advanced in the motorsport field, enabling the production of custom lightweight components with high-performance alloys. Rapid design iterations and short production lead times make AM ideal to improve component performance. However, predicting fatigue resistance remains challenging due to the inherent presence of manufacturing defects. This work presents the application of a defect-tolerant methodology to predict the impact of manufacturing defects on component performance under operating conditions. First, the manufacturing defects of standard fatigue specimens and a selected component were revealed by X-ray Computed Tomography. Then, machine learning-assisted Extreme Value Statistics was adopted to estimate the occurrence of different defect types in critical regions of the component. Finally, a probabilistic fracture-based design model was applied to quantify the influence of defect size on fatigue performance.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"76 ","pages":"Pages 138-144"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ideal sintering behaviours as a semi-crystalline thermoplastic polymer makes polyamide 12 (PA12) the most widely used material for Selective Laser Sintering (SLS) printing technique. However, the presence of defects, such as partially melted particles, compromise the structural integrity of the printed components influencing their mechanical behaviours especially in terms of fatigue life. Estimating fatigue properties is a resource-intensive process, both in terms of material and time, particularly within the rapidly evolving AM industry. If the desired properties are not achieved, the manufacturing process must be restarted with adjustments to one or more printing parameters. In this context, the need to rapidly verify the mechanical properties of components has become increasingly critical. Over the years, numerous energy-based methods have been developed to expedite the study of fatigue properties in materials, thanks to the dissipative nature of the fatigue process. Among these, the Thermographic Methods (TMs) have shown simplicity of application and rapidity to obtain results. In this work the mechanical properties of PA12 specimens obtained with SLS technique have been investigated using the Risitano’s Thermographic Method (RTM) and the Static Thermographic Method (STM). The influence of the printing direction has been analysed testing two sets of specimen’s configurations. The difference in terms of energetic release during quasi-static and fatigue tests for both configurations have been highlighted and discussed. The study demonstrates the potential of thermography as a technique for evaluating the fatigue life of polymeric materials produced by SLS, opening new perspectives for quality control and optimization of AM production processes.
{"title":"Innovative and rapid thermographic approaches for the evaluation of fatigue life of SLS PA12","authors":"Davide D’Andrea , Davide Crisafulli , Filippo Berto , Giacomo Risitano , Dario Santonocito","doi":"10.1016/j.prostr.2025.12.299","DOIUrl":"10.1016/j.prostr.2025.12.299","url":null,"abstract":"<div><div>The ideal sintering behaviours as a semi-crystalline thermoplastic polymer makes polyamide 12 (PA12) the most widely used material for Selective Laser Sintering (SLS) printing technique. However, the presence of defects, such as partially melted particles, compromise the structural integrity of the printed components influencing their mechanical behaviours especially in terms of fatigue life. Estimating fatigue properties is a resource-intensive process, both in terms of material and time, particularly within the rapidly evolving AM industry. If the desired properties are not achieved, the manufacturing process must be restarted with adjustments to one or more printing parameters. In this context, the need to rapidly verify the mechanical properties of components has become increasingly critical. Over the years, numerous energy-based methods have been developed to expedite the study of fatigue properties in materials, thanks to the dissipative nature of the fatigue process. Among these, the Thermographic Methods (TMs) have shown simplicity of application and rapidity to obtain results. In this work the mechanical properties of PA12 specimens obtained with SLS technique have been investigated using the Risitano’s Thermographic Method (RTM) and the Static Thermographic Method (STM). The influence of the printing direction has been analysed testing two sets of specimen’s configurations. The difference in terms of energetic release during quasi-static and fatigue tests for both configurations have been highlighted and discussed. The study demonstrates the potential of thermography as a technique for evaluating the fatigue life of polymeric materials produced by SLS, opening new perspectives for quality control and optimization of AM production processes.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"76 ","pages":"Pages 151-158"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.083
H. Lopes , J.V. Araújo dos Santos , M.A.P. Vaz
This paper presents a novel method for identifying multiple internal damages in laminated composite plates using filtered phase maps acquired by digital shearography (DS). The technique analyzes interference phases acquired at fixed intervals during the cooling phase after a pulsed thermal load. By correlating consecutive interference phases, a phase map is generated for each step. These maps are then processed: first, a band-pass filter isolates the small phase deviations caused by internal damage; second, the filtered maps are coherently summed to enhance the damage-induced signal against background noise significantly. The effectiveness of the method is demonstrated on a carbon-fiber-reinforced polymer (CFRP) plate containing two internal damages from low-energy impacts. Results show that the filtered phase maps enable superior identification of both the location and size of the damage compared to standard post-processing techniques. Furthermore, generating phase maps between small time intervals minimizes speckle decorrelation, and the subsequent summation step effectively mitigates random distortions from air convection and external vibrations, yielding filtered maps with a significantly better signal-to-noise ratio (SNR). The influence of the shearing direction on damage detectability is also investigated. Overall, this approach provides a robust and enhanced evaluation of damage in composite structures.
{"title":"Improving Damage Identification by Shearography Phase Map Analysis","authors":"H. Lopes , J.V. Araújo dos Santos , M.A.P. Vaz","doi":"10.1016/j.prostr.2026.01.083","DOIUrl":"10.1016/j.prostr.2026.01.083","url":null,"abstract":"<div><div>This paper presents a novel method for identifying multiple internal damages in laminated composite plates using filtered phase maps acquired by digital shearography (DS). The technique analyzes interference phases acquired at fixed intervals during the cooling phase after a pulsed thermal load. By correlating consecutive interference phases, a phase map is generated for each step. These maps are then processed: first, a band-pass filter isolates the small phase deviations caused by internal damage; second, the filtered maps are coherently summed to enhance the damage-induced signal against background noise significantly. The effectiveness of the method is demonstrated on a carbon-fiber-reinforced polymer (CFRP) plate containing two internal damages from low-energy impacts. Results show that the filtered phase maps enable superior identification of both the location and size of the damage compared to standard post-processing techniques. Furthermore, generating phase maps between small time intervals minimizes speckle decorrelation, and the subsequent summation step effectively mitigates random distortions from air convection and external vibrations, yielding filtered maps with a significantly better signal-to-noise ratio (SNR). The influence of the shearing direction on damage detectability is also investigated. Overall, this approach provides a robust and enhanced evaluation of damage in composite structures.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"77 ","pages":"Pages 673-680"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.074
Francisco Afonso , Pedro J.S.C.P. Sousa , Francisco Sousa , Susana Dias , Paulo J. Tavares , Pedro M.G.J. Moreira , Cassiano Linhares , Helena Lopes
The analysis of vibration is a widely used method for structure or equipment health monitoring, since structural faults may alter its vibration behaviour. Usually performed using contact methods, mainly accelerometers, certain restraints such as structural fragility, mass loading, or accessibility limitations may require alternative approaches. In this study, preliminary tests were conducted to evaluate event-based (also known as neuromorphic) imaging, comparing it with conventional frame camera approaches. A 120 mm fan served as the specimen, tested while balanced and unbalanced by a small mass. Baseline rotation speed measurements using a tachometer were 32.5 rotations per second (rps) while balanced and 31.8 rps while unbalanced. The unbalanced fan was tested with an accelerometer, showing a peak near 31 Hz along the motor axis. Hardware included a Prophesee EVK4 neuromorphic camera, a Basler a2A1920-160umBAS frame camera, a Prophesee 8 mm lens, a macro-lens assembly (4.0× magnification) and printed targets (striped bands, grid and a printed gradient resembling a speckle pattern). The final configurations were: neuromorphic camera with standard lens and unbalanced fan; accelerometer with unbalanced fan; neuromorphic camera with macro lens and balanced fan; and frame camera with macro lens and balanced fan. Event data showed dominant frequencies at 31.6 Hz (Neuromorphic camera with standard lens and unbalanced fan) and 32.3 Hz (Neuromorphic camera with macro lens and balanced fan), aligning with the 31.0 Hz accelerometer peak and the tachometer baselines, respectively. For the frame camera with macro lens, image tracking and digital image correlation (DIC) both revealed a peak around 33.0 Hz; however, in the DIC analysis, it was not clearly dominant. Overall, neuromorphic imaging provided a simple setup that returned the dominant frequency in good agreement with frame-based and accelerometer results. Frame tracking offered richer results, but required external triggering and synchronization. This work is a result of Agenda “ATE – Aliança para a Transição Energética”, nr C644914747-00000023, investment project nr 56, financed by the Recovery and Resilience Plan (PRR) and by European Union – NextGeneration EU.
振动分析是一种广泛应用于结构或设备健康监测的方法，因为结构故障可能会改变其振动行为。通常使用接触法，主要是加速度计，某些限制，如结构脆弱性，质量载荷或可达性限制可能需要替代方法。在这项研究中，进行了初步测试来评估基于事件（也称为神经形态）的成像，并将其与传统的帧相机方法进行比较。一个120毫米的风扇作为试样，在平衡和不平衡的情况下进行小质量的测试。使用转速计测量的基线转速在平衡时为32.5转/秒（rps），在不平衡时为31.8转/秒。用加速度计测试不平衡风扇，显示沿电机轴接近31 Hz的峰值。硬件包括一个先知EVK4神经形态相机，Basler a2A1920-160umBAS框架相机，一个先知8毫米镜头，一个微距镜头组件（4.0倍放大）和打印目标（条纹带，网格和类似斑点图案的打印梯度）。最终配置为：标准镜头和不平衡风扇的神经形态相机；带有不平衡风扇的加速度计；带有微距镜头和平衡风扇的神经形态相机；并配有微距镜头和平衡风扇的相框相机。事件数据显示，优势频率分别为31.6 Hz（带有标准镜头和不平衡风扇的Neuromorphic相机）和32.3 Hz（带有微距镜头和平衡风扇的Neuromorphic相机），与加速度计31.0 Hz的峰值和转速计基线一致。对于微距镜头的框架相机，图像跟踪和数字图像相关（DIC）都在33.0 Hz左右出现峰值；然而，在DIC分析中，它并不明显占主导地位。总的来说，神经形态成像提供了一个简单的设置，返回的主导频率与基于帧和加速度计的结果非常一致。帧跟踪提供了更丰富的结果，但需要外部触发和同步。这项工作是由恢复和复原力计划（PRR）和欧洲联盟-下一代欧盟资助的第56号投资项目（编号C644914747-00000023）“ATE - alian para a transo energysas”议程的成果。
{"title":"Non-contact vibration measurement using event-based neuromorphic imaging","authors":"Francisco Afonso , Pedro J.S.C.P. Sousa , Francisco Sousa , Susana Dias , Paulo J. Tavares , Pedro M.G.J. Moreira , Cassiano Linhares , Helena Lopes","doi":"10.1016/j.prostr.2026.01.074","DOIUrl":"10.1016/j.prostr.2026.01.074","url":null,"abstract":"<div><div>The analysis of vibration is a widely used method for structure or equipment health monitoring, since structural faults may alter its vibration behaviour. Usually performed using contact methods, mainly accelerometers, certain restraints such as structural fragility, mass loading, or accessibility limitations may require alternative approaches. In this study, preliminary tests were conducted to evaluate event-based (also known as neuromorphic) imaging, comparing it with conventional frame camera approaches. A 120 mm fan served as the specimen, tested while balanced and unbalanced by a small mass. Baseline rotation speed measurements using a tachometer were 32.5 rotations per second (rps) while balanced and 31.8 rps while unbalanced. The unbalanced fan was tested with an accelerometer, showing a peak near 31 Hz along the motor axis. Hardware included a Prophesee EVK4 neuromorphic camera, a Basler a2A1920-160umBAS frame camera, a Prophesee 8 mm lens, a macro-lens assembly (4.0× magnification) and printed targets (striped bands, grid and a printed gradient resembling a speckle pattern). The final configurations were: neuromorphic camera with standard lens and unbalanced fan; accelerometer with unbalanced fan; neuromorphic camera with macro lens and balanced fan; and frame camera with macro lens and balanced fan. Event data showed dominant frequencies at 31.6 Hz (Neuromorphic camera with standard lens and unbalanced fan) and 32.3 Hz (Neuromorphic camera with macro lens and balanced fan), aligning with the 31.0 Hz accelerometer peak and the tachometer baselines, respectively. For the frame camera with macro lens, image tracking and digital image correlation (DIC) both revealed a peak around 33.0 Hz; however, in the DIC analysis, it was not clearly dominant. Overall, neuromorphic imaging provided a simple setup that returned the dominant frequency in good agreement with frame-based and accelerometer results. Frame tracking offered richer results, but required external triggering and synchronization. This work is a result of Agenda “ATE – Aliança para a Transição Energética”, nr C644914747-00000023, investment project nr 56, financed by the Recovery and Resilience Plan (PRR) and by European Union – NextGeneration EU.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"77 ","pages":"Pages 584-592"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.059
Ercan Işik , Fatih Avcil , Aydın Büyüksaraç , Enes Arkan , Silva Lozančić , Dorin Radu , Marijana Hadzima-Nyarko
Deficiencies in reinforced-concrete (RC) elements, such as inadequate transverse reinforcement and poor material quality, critically compromise structural integrity by accelerating fracture mechanisms and reducing overall structural capacity. The February 6, 2023 Kahramanmaraş earthquakes (Mw 7.7 and Mw 7.6) caused severe damage to reinforced concrete (RC) structures in south-eastern Türkiye, highlighting the critical influence of concrete quality and transverse reinforcement detailing on fracture behaviour and structural integrity. Field surveys revealed widespread deficiencies, including excessive stirrup spacing, inadequate diameters, insufficient hook anchorage, poor material quality, and workmanship flaws. Integrating post-earthquake observations with nonlinear static analyses of a representative 6-storey RC model, 10 parametric simulations examined the effects of transverse spacing, diameter, hook angle, and material grade. Results show that closer stirrup spacing (300 mm to 200 mm) can raise column shear capacity by up to 22%, while 135° hook anchorage mitigates longitudinal bar buckling. The combined field–numerical approach offers evidence-based recommendations for seismic design, and code improvement in high-risk regions.
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Pub Date : 2026-01-01DOI: 10.1016/j.prostr.2026.01.071
Vasco Gomes , Alexandre B. Santos , Daniela I.M. Azevedo , Tiago M.R.M. Domingues , Susana Dias , Pedro M.G.P. Moreira , Tiago T.M. Soares , António da S. Guedes
Servo presses spend most of their lifecycle performing cutting and stamping operations, which gradually lead to mechanical deterioration. On top of that, misuse and fatigue can introduce issues which, if left unattended, will cause major equipment failure. The detection of anomalous situations before damage propagation throughout several components, as well as the understanding of their health condition, is crucial for failure prediction. To support this, digital twins can be integrated into maintenance programs to enable real-time monitoring, simulation, diagnosis and prognostics. Digital twin simulations make it possible to visualise the impact of changes in operational or structural parameters. Therefore, this work focuses on the simulation of a real 4000 kN servo press for blanking processes, manufactured by Mecânica Exacta.
A multibody system (MBS) of the 4000 kN servo press was developed in SimulationX ® software to study its dynamic behaviour. Components were modelled as rigid bodies connected through linear and revolution joints. The dynamic behaviour of the servo press was assessed under different loading conditions, including without loading, under balanced and unbalanced loading. This allowed the identification of critical regions, regarding vibration, mechanical loading and power losses due to contact between the slide and frame. Additional features, such as pneumatic counterbalancing cylinders and plain journal bearings, were also included in the model.
The integration of these simulations with real-time monitoring of the servo press, using several sensors, allows for a more reliable and efficient condition monitoring. By providing a virtual counterpart, the digital twin becomes a valuable tool for understanding the system’s behaviour beyond what can be inferred from sensor measurements alone.
伺服压力机在其生命周期的大部分时间用于切割和冲压操作，这逐渐导致机械性能恶化。最重要的是，误用和疲劳会带来问题，如果不加以注意，将导致重大设备故障。在多个部件的损伤传播之前检测异常情况，以及了解其健康状况，对于故障预测至关重要。为了支持这一点，数字孪生可以集成到维护程序中，以实现实时监控、模拟、诊断和预测。数字孪生模拟可以可视化操作或结构参数变化的影响。因此，这项工作的重点是模拟一个真正的4000千牛伺服压力机的下料过程，由mec nica Exacta制造。利用SimulationX®软件对4000kn伺服压力机的多体系统（MBS）进行了动态特性研究。组件被建模为通过线性和旋转关节连接的刚体。对伺服压力机在不同加载条件下的动态特性进行了评估，包括无加载、平衡加载和不平衡加载。这允许识别关键区域，关于振动，机械载荷和动力损失，由于滑动和框架之间的接触。附加功能，如气动平衡缸和滑动轴颈轴承，也包括在模型中。将这些模拟与伺服压力机的实时监测相结合，使用多个传感器，可以实现更可靠、更有效的状态监测。通过提供一个虚拟的对等体，数字孪生体成为理解系统行为的一个有价值的工具，而不仅仅是从传感器测量中推断出来的。
{"title":"Multibody Dynamic System for Servo Press Condition Monitoring","authors":"Vasco Gomes , Alexandre B. Santos , Daniela I.M. Azevedo , Tiago M.R.M. Domingues , Susana Dias , Pedro M.G.P. Moreira , Tiago T.M. Soares , António da S. Guedes","doi":"10.1016/j.prostr.2026.01.071","DOIUrl":"10.1016/j.prostr.2026.01.071","url":null,"abstract":"<div><div>Servo presses spend most of their lifecycle performing cutting and stamping operations, which gradually lead to mechanical deterioration. On top of that, misuse and fatigue can introduce issues which, if left unattended, will cause major equipment failure. The detection of anomalous situations before damage propagation throughout several components, as well as the understanding of their health condition, is crucial for failure prediction. To support this, digital twins can be integrated into maintenance programs to enable real-time monitoring, simulation, diagnosis and prognostics. Digital twin simulations make it possible to visualise the impact of changes in operational or structural parameters. Therefore, this work focuses on the simulation of a real 4000 kN servo press for blanking processes, manufactured by Mecânica Exacta.</div><div>A multibody system (MBS) of the 4000 kN servo press was developed in SimulationX ® software to study its dynamic behaviour. Components were modelled as rigid bodies connected through linear and revolution joints. The dynamic behaviour of the servo press was assessed under different loading conditions, including without loading, under balanced and unbalanced loading. This allowed the identification of critical regions, regarding vibration, mechanical loading and power losses due to contact between the slide and frame. Additional features, such as pneumatic counterbalancing cylinders and plain journal bearings, were also included in the model.</div><div>The integration of these simulations with real-time monitoring of the servo press, using several sensors, allows for a more reliable and efficient condition monitoring. By providing a virtual counterpart, the digital twin becomes a valuable tool for understanding the system’s behaviour beyond what can be inferred from sensor measurements alone.</div></div>","PeriodicalId":20518,"journal":{"name":"Procedia Structural Integrity","volume":"77 ","pages":"Pages 559-566"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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