Experimental Mechanics最新文献

{"title":"On the Cover: An Internal Digital Image Correlation Technique for High-Strain Rate Dynamic Experiments","authors":"","doi":"10.1007/s11340-025-01162-5","DOIUrl":"10.1007/s11340-025-01162-5","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"305 - 305"},"PeriodicalIF":2.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding the Incident Wave Errors in Split Hopkinson Pressure Bar Test with Machine Learning Method","authors":"K. Wang,&nbsp;Y. Wu,&nbsp;X. Zhou,&nbsp;Y. Yu,&nbsp;L. Xu,&nbsp;G. Gao","doi":"10.1007/s11340-025-01146-5","DOIUrl":"10.1007/s11340-025-01146-5","url":null,"abstract":"<div><h3>Background</h3><p>In Split Hopkinson Pressure Bar (SHPB) test, the misalignment of the striker bar leads to waveform errors in the incident wave, which results in inaccurate material mechanical property parameters.</p><h3>Objective</h3><p>The goal of this paper is to apply machine learning (ML) method to understand waveform errors in incident waves (error peak-valley features) and investigate the impact of imperfect striker bar on the incident wave.</p><h3>Methods</h3><p>ML projects were constructed by developing numerical models to establish waveform databases based on experimental data, and the continuous optimization of ML projects advances the application of a dual-output average curve (DOAC) method simulating the use of two strain gauges for error processing.</p><h3>Results</h3><p>The waveform errors were categorized into two types: non-parallel impact and parallel non-coaxial impact by continuously optimizing the ML model through error analysis, successfully understanding up to 24 types of waveforms. DOAC effectively eliminated the bending effect, and the error effects were decomposed into bending effects and other effects.</p><h3>Conclusion</h3><p>The high-accuracy ML results provide simple and real-time automatic correction solutions for waveform errors and quantify the errors, closing the loop between numerical simulation and experiments. The error and dispersion coupling effects can be successfully decoupled using DOAC, suggesting that bending waves are the main cause of error effects with the dominant bending effects.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 2","pages":"283 - 303"},"PeriodicalIF":2.0,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Internal Digital Image Correlation Technique for High-Strain Rate Dynamic Experiments","authors":"B.P. Lawlor,&nbsp;V. Gandhi,&nbsp;G. Ravichandran","doi":"10.1007/s11340-025-01149-2","DOIUrl":"10.1007/s11340-025-01149-2","url":null,"abstract":"<div><h3>Background</h3><p>Full-field, quantitative visualization techniques, such as digital image correlation (DIC), have unlocked vast opportunities for experimental mechanics. However, DIC has traditionally been a surface measurement technique, and has not been extended to perform measurements on the interior of specimens for dynamic, full-scale laboratory experiments. This limitation restricts the scope of physics which can be investigated through DIC measurements, especially in the context of heterogeneous materials.</p><h3>Objective</h3><p>The focus of this study is to develop a method for performing internal DIC measurements in dynamic experiments. The aim is to demonstrate its feasibility and accuracy across a range of stresses (up to <span>(650,)</span>MPa), strain rates (<span>(10^{3})</span>-<span>(10^6,)</span>s<span>(^{-1})</span>), and high-strain rate loading conditions (e.g., ramped and shock wave loading).</p><h3>Methods</h3><p>Internal DIC is developed based on the concept of applying a speckle pattern at an inner-plane of a transparent specimen. The high-speed imaging configuration is coupled to the traditional dynamic experimental setups, and is focused on the internal speckle pattern. During the experiment, while the sample deforms dynamically, in-plane, two-dimensional deformations are measured via correlation of the internal speckle pattern. In this study, the viability and accuracy of the internal DIC technique is demonstrated for split-Hopkinson (Kolsky) pressure bar (SHPB) and plate impact experiments.</p><h3>Results</h3><p>The internal DIC experimental technique is successfully demonstrated in both the SHPB and plate impact experiments. In the SHPB setting, the accuracy of the technique is excellent throughout the deformation regime, with measurement noise of approximately <span>(0.2%)</span> strain. In the case of plate impact experiments, the technique performs well, with error and measurement noise of <span>(1%)</span> strain.</p><h3>Conclusion</h3><p>The internal DIC technique has been developed and demonstrated to work well for full-scale dynamic high-strain rate and shock laboratory experiments, and the accuracy is quantified. The technique can aid in investigating the physics and mechanics of the dynamic behavior of materials, including local deformation fields around dynamically loaded material heterogeneities.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"407 - 419"},"PeriodicalIF":2.0,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554140","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Density-Dependent Cell Structure of EPP Bead Foams Under Compression","authors":"I. Koch,&nbsp;G. Preiß,&nbsp;M. Müller-Pabel,&nbsp;B. Grüber,&nbsp;M. Gude","doi":"10.1007/s11340-025-01151-8","DOIUrl":"10.1007/s11340-025-01151-8","url":null,"abstract":"<div><h3>Background</h3><p>Closed cell polymer bead foams are widely used in industrial applications due to their extraordinary damping and insulation properties. To understand the structure-property-relations at different deformation states the volumetric structure of polymer walls, cells and beads should be statistically analysed.</p><h3>Objective</h3><p>The presented work is focused on the statistical analysis of the changing cell structure of expanded polypropylene bead foams of different density at distinct compression states.</p><h3>Methods</h3><p>Cylindrical bead foam specimens are scanned by x-ray computed tomography at 3-5 different compression states. The reconstructed volume information is segmented and statistically analysed.</p><h3>Results</h3><p>It could be shown that, among others, the cell sphericity and their orientation relative to the plane normal to the loading direction are sensitive parameters to the deformation state. With regard to the material symmetry level, a shift of the isotropic foam to transversal isotropic structure was observed. No sudden, stability related, deformation or failure could be observed.</p><h3>Conclusions</h3><p>Good metrics for the deformation analysis of expanded polypropylene bead foams from <i>in-situ</i> computed tomography tests are the cell sphericity and orientation. Compression deformation leads to a gradually change of material symmetry level from isotropy to anisotropy.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"397 - 406"},"PeriodicalIF":2.0,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01151-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143553797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Material Orientation and Degree of Deformation on the Tension–Compression Asymmetry of AA2024‒T4","authors":"H. Wang,&nbsp;Y. Wang,&nbsp;A. Yu,&nbsp;M. Gu,&nbsp;G. Chen,&nbsp;X. Li","doi":"10.1007/s11340-025-01147-4","DOIUrl":"10.1007/s11340-025-01147-4","url":null,"abstract":"<div><h3>Background</h3><p>Accurate prediction of the plastic behavior of AA2024‒T4 requires a deep understanding of the mechanical response of the material under different loading conditions. For alloy sheets, the material orientation and deformation are two important factors whose effects should be clarified.</p><h3>Objective</h3><p>This work focuses on the complex relationships among the material orientation, deformation, and tension‒compression asymmetry of AA2024‒T4.</p><h3>Methods</h3><p>The tension, compression, and shear responses of materials at different orientations are experimentally investigated through dog bone, cuboid, and butterfly specimen, respectively. In addition, the tension‒compression asymmetry is embedded in the anisotropic parameters rather than an additional independent parameter.</p><h3>Results</h3><p>Tension‒compression asymmetry is sensitive to orientation and degree of deformation. The tension‒compression asymmetry tends to be stable with increasing degree of deformation. But the evolution law of tension–compression asymmetry can be affected by orientation.</p><h3>Conclusions</h3><p>An additional parameter describing the asymmetry is required for isotropic plastic modeling. This parameter can be ignored when the anisotropic situation is considered because such an effect will be implied in the anisotropic parameters. In addition, the influence of degree of deformation on tension–compression asymmetry and plastic anisotropy can be reflected by the evolutions of anisotropic parameters.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 2","pages":"255 - 268"},"PeriodicalIF":2.0,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Cover: Physics Informed Neural Network Based Digital Image Correlation Method","authors":"","doi":"10.1007/s11340-025-01152-7","DOIUrl":"10.1007/s11340-025-01152-7","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 2","pages":"175 - 175"},"PeriodicalIF":2.0,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improving Metrological Performance Estimation of Digital Volume Correlation: Application to X-Ray Computed Tomography","authors":"S. Wantz,&nbsp;R. Brault,&nbsp;Y. Pannier,&nbsp;V. Valle","doi":"10.1007/s11340-025-01145-6","DOIUrl":"10.1007/s11340-025-01145-6","url":null,"abstract":"<div><h3>Background</h3><p>This study reports on the performance estimation of Digital Volume Correlation (DVC) for tomographic applications. The performance of DVC can be evaluated in terms of two distinct errors: the random error, directly linked to image quality, and the interpolation error, which is the one of the most significant systematic error generated by DVC algorithms. However, the existing methods provide only a limited estimate of the interpolation error, or allow only the random error to be assessed.</p><h3>Objective</h3><p>A new method is proposed to evaluate the interpolation error coupled with the random error in a simple and fast way to assess the overall performance of DVC for any tomographic application.</p><h3>Methods</h3><p>This new method proposes to apply a rotation to the sample (instead of the usual translation) to evaluate the interpolation error. This rotational movement generates linearly varying displacement fields, and each point of a displacement field describes a distinct non-integer voxel position. As this rotation is a rigid body motion, the random error associated with tomographic noise is also taken into account.</p><h3>Results</h3><p>This new method can generate several thousand interpolation error measurement points in only two acquisitions, allowing a very detailed and local assessment of this error. Additionally, and compared to existing methods in the literature (repeat scan), this method does not underestimate the random error, essential for assessing the overall performance of the DVC.</p><h3>Conclusions</h3><p>The proposed method efficiently evaluates DVC performance by accurately assessing both interpolation and random errors through rotational sample movement, improving the reliability in DVC measurements.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 2","pages":"269 - 282"},"PeriodicalIF":2.0,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143513270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of Fatigue Limit for Aluminum Alloy Laser Welds Based on Dissipated Energy","authors":"T. Yamamoto,&nbsp;Y. Ogawa,&nbsp;M. Hayashi,&nbsp;K. Kadoi,&nbsp;D. Shiozawa,&nbsp;T. Sakagami","doi":"10.1007/s11340-025-01148-3","DOIUrl":"10.1007/s11340-025-01148-3","url":null,"abstract":"<div><h3>Background</h3><p>Laser welding has a faster processing speed than other welding techniques. However, defects can occur under various welding conditions, and high safety and reliability are required for applying laser welding to actual mechanical structures.</p><h3>Objective</h3><p>This study focused on estimating the fatigue limit by dissipated energy which is the energy loss resulting in fatigue damage owing to localized plastic deformation. This study was conducted to determine whether the fatigue limit of aluminum alloy laser welds can be rapidly estimated using the dissipated energy.</p><h3>Methods</h3><p>In a test with a stepwise increase in stress amplitude, the dissipated energy and the strain were measured by infrared thermography and digital image correlation from displacement measurements with a visible camera, respectively. In the fatigue limit estimation using dissipated energy, the fatigue limit is determined by the empirical rule that the stress amplitude with increasing the dissipated energy is the estimated fatigue limit.</p><h3>Results</h3><p>Laser welds exhibited the highest dissipated energy at the fracture origin of the joint. Therefore, the crack initiation point of welded joints can be visualized by measuring the dissipated energy. If the boundary value of both groups in the domain decomposition method using the least-squares approximation is the estimated fatigue limit, the estimated fatigue limits for the aluminum alloy laser welds and those base material specimens are almost consistent with the actual fatigue limits.</p><h3>Conclusions</h3><p>The fatigue limit estimation using the dissipated energy can be applied to aluminum alloy laser welds.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"385 - 395"},"PeriodicalIF":2.0,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01148-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Inverse Parameter Identification in Finite Element Problems Using Machine Learning-Aided Optimization Framework","authors":"A. Tariq,&nbsp;B. Deliktaş","doi":"10.1007/s11340-024-01136-z","DOIUrl":"10.1007/s11340-024-01136-z","url":null,"abstract":"<div><h3>Background</h3><p>The ability of finite element analysis to produce high fidelity results is greatly dependent on quality of constitutive model and the accuracy of their parameters. As such, the calibration of phenomenological constitutive models to replicate real-world behaviors has remained a focal point of many research works.</p><h3>Objective</h3><p>A new inverse identification approach combining numerical-experimental methods and data-driven techniques to characterize the nonlinear response of materials using a single experiment is proposed.</p><h3>Methods</h3><p>This approach integrates finite element analysis, optimization methods and machine learning techniques, such as Artificial Neural Networks and Support Vector Regression, to accurately determine model parameters while significantly reducing computational time. This approach can be used to characterize a wide range of models irrespective of the number of parameters involved. A detailed flowchart of the methodology focusing on its implementation aspects is provided and its each module is explained.</p><h3>Results</h3><p>The proposed model calibration approach successfully identified eight parameters for a cohesive zone model implemented in user element subroutine (UEL), four parameters for a hardening model implemented in user material subroutine (UMAT), and five parameters for a Johnson–Cook plasticity model. In all cases, this method achieved an excellent fit between the simulation and experimental results. Moreover, it demonstrated a significant improvement in efficiency, being 2–3 times faster than traditional optimization algorithms in determining optimal parameters.</p><h3>Conclusions</h3><p>Based on the presented investigations, the proposed machine learning-based inverse method can significantly accelerate the parameter identification procedure and can be extended to a wide range of material models.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"325 - 349"},"PeriodicalIF":2.0,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Torsional Performance of Vat-Photopolymerized Tough Resin: Influence of Gauge Length and UV Post-Curing","authors":"H. Sadaghian,&nbsp;S. Khalilzadehtabrizi,&nbsp;S. Khodadoost,&nbsp;J.H. Yeon","doi":"10.1007/s11340-024-01135-0","DOIUrl":"10.1007/s11340-024-01135-0","url":null,"abstract":"<div><h3>Background</h3><p>A myriad of materials, ranging from soft sensors to bone substitutes, undergo torsional loading throughout their operational lifespan. Many of these materials are produced using additive manufacturing (AM) technology due to its broad applicability. Understanding the torsional behavior of these AM components is crucial prior to their utilization. However, research on the torsional behavior of solid additively-manufactured resin polymers remains very limited.</p><h3>Objective</h3><p>To address the gap in understanding the torsional behavior of additively-manufactured resin polymers, this study aimed to investigate the effect of varying gage lengths and UV post-curing durations on the torsional capacity, shear modulus, and energy absorption characteristics of these materials.</p><h3>Methods</h3><p>Torsion specimens were fabricated using vat photopolymerization (VPP) with <i>AnyCubic</i> UV Tough Resin. The specimens were prepared with different gage lengths (20, 40, 60, and 80 mm) and were subjected to five UV post-curing durations (0, 15, 30, 60, 90, and 120 min). Monotonic torsion was applied to the specimens until failure at a rate of 0.1 revolutions per minute.</p><h3>Results</h3><p>The tests revealed ductile failure patterns across all specimens. Longer post-curing times were found to correlate with increased torsional capacities and shear moduli. However, conclusions regarding energy absorption per unit volume remained inconclusive. The results showed that UV exposure had a significantly greater impact on the mechanical properties of the specimens compared to the gage length. Additionally, a normalized trilinear model was proposed to characterize the behavior of additively-manufactured resin polymers under monotonic torsion, which facilitates numerical simulation of material responses in finite element software.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 3","pages":"365 - 384"},"PeriodicalIF":2.0,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-024-01135-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143554016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}