Experimental Mechanics最新文献

{"title":"Microstructure Clones","authors":"K.M. Fitzgerald,&nbsp;W. Gilliland,&nbsp;H. Lim,&nbsp;T. Ruggles,&nbsp;N. Aragon,&nbsp;J.D. Carroll","doi":"10.1007/s11340-025-01158-1","DOIUrl":"10.1007/s11340-025-01158-1","url":null,"abstract":"<div><h3>Background</h3><p>A material’s microstructure drives its material performance. Contemporary crystal plasticity experiments compare full-field strain measurements of polycrystal specimens to models. Because each specimen is unique, it is impossible to know which features of the observed deformation are deterministic vs statistical; thus, differences between model and experiment may or may not be significant.</p><h3>Objective</h3><p>This paper introduces the invention of microstructure clones. Microstructure clones are 2D oligocrystal specimens that have nearly identical microstructures to remedy the aforementioned experimental limitations. Having specimens with nearly identical microstructures will allow for multiple destructive tests of a microstructure (either as repeats or intentionally different experiments), an ability to “see the future” by providing insight into how a specimen will deform, variability quantification, and experimental investigations of response to small microstructural changes.</p><h3>Methods</h3><p>This work introduces microstructure clones. Repeatability of these clones is demonstrated in tensile bars of pure nickel. Local strain measurements from digital image correlation are compared between clone specimens and compared to results from a crystal plasticity finite element model.</p><h3>Results</h3><p>Two sets of microstructure clones were tested in this study and displayed very consistent deformation responses within each clone set. Small observed differences in deformation invite investigation into microstructure stochasticity and the effect of small microstructural and loading differences.</p><h3>Conclusions</h3><p>Microstructure clones represent a significant shift in understanding structure–property relationships. This work reshapes experimental crystal plasticity to allow for experiments that control for specific variables, quantification of microstructural stochasticity (and other sources of stochasticity), and opportunities for replicating experiments.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"729 - 742"},"PeriodicalIF":2.0,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01158-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073677","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":"Thermodynamic Investigation of Glassy Polycarbonate Under Slow Torsion by Experimentally Characterizing Adiabatic Temperature Rise","authors":"S. Wu,&nbsp;W. Li,&nbsp;L. Zhuo,&nbsp;J. Zhu,&nbsp;G. Xie,&nbsp;W. Zhang,&nbsp;P. Singhatanadgid,&nbsp;D. Zhang","doi":"10.1007/s11340-025-01156-3","DOIUrl":"10.1007/s11340-025-01156-3","url":null,"abstract":"<div><h3>Background</h3><p>Amorphous polymers are widely employed in engineering applications where their constitutive models need to be verified using characterization data such as synchronous stress–strain and plastic dissipation. It is convenient to conduct slow strain rate experiments, but measuring the adiabatic temperature rise remains challenging because the estimation of the heat transfer still has a lack of accuracy.</p><h3>Objective</h3><p>A suitable method was developed for simultaneously measuring stress–strain and adiabatic temperature for polycarbonate subjected to slow torsion (&lt; 1 s⁻¹).</p><h3>Methods</h3><p>The thermal and mechanical responses were measured through synchronizing the digital image correlation, IR thermography and the sensors of torsion machine. The related adiabatic temperature can be calculated by prescribing the equivalent heat transfer using a simple convection model, whose coefficient was determined using a parametric fitting based on the measurement of temperature drop after the mechanical loading. To obtain the precise heat calculation, an ideal convection coefficient was established by using the earlier stage of the temperature drop because the primary form of heat transmission at this stage was convection. At last, a plastic work-to-heat conversion model with a Taylor-Quinney coefficient was used to validate the characterized results.</p><h3>Results</h3><p>It shows that three and a quarter cycles of reversed cyclic shear strains from -0.51 to 0.43 will result in an increase in the adiabatic temperature of roughly 45˚C. This value agrees well with the theoretical value of about 47 ˚C calculated using the Taylor-Quinney coefficient.</p><h3>Conclusions</h3><p>An experimental method for glassy polycarbonate’s thermodynamic investigation under slow torsion is established based on the accurate estimation of adiabatic temperature rise in the presence of heat transfer.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"717 - 728"},"PeriodicalIF":2.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073971","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":"A Modified Losipescu Method for Evaluating In-Situ Shear Behavior Using High-Temperature X-Ray Computed Tomography","authors":"W. Lu,&nbsp;X. Li,&nbsp;W. Du,&nbsp;R. Huang,&nbsp;Y. Chen,&nbsp;Z. Qu","doi":"10.1007/s11340-025-01163-4","DOIUrl":"10.1007/s11340-025-01163-4","url":null,"abstract":"<div><h3>Background</h3><p>Ceramic matrix composites (CMCs) are widely used in high-temperature environments, and due to their low shear strength, failure is primarily governed by shear performance. It is imperative to reveal their shear failure mechanism in-situ under high-temperature conditions.</p><h3>Objective</h3><p>The in-situ shear test of CMCs under high-temperature conditions was realized through the improved Iosipescu method.</p><h3>Methods</h3><p>Based on the traditional Iosipescu method, this study proposes an improved small-scale Iosipescu method with fewer parts and without threaded fastening parts. Furthermore, this method can be applied to high-temperature in-situ loading.</p><h3>Results</h3><p>The specimen's stress field and failure mode were obtained via numerical simulation under the improved Iosipescu method. The in-plane shear strength (IPSS) of the 2D-C/SiC composites from room temperature (RT) to 1100 °C was tested under atmospheric conditions using the improved Iosipescu method. The results showed that the IPSS of the 2D-C/SiC composites increased as the temperature rose to 900 °C and then decreased as the temperature continued to rise. Furthermore, the in-situ shear test of 2D-C/SiC composite materials at 900 °C was performed using the improved Iosipescu method. From the analysis of the tomographic images, it can be seen that the specimen had void defects before the load was applied, and as the load increased, composite material damage began to develop along the original defects until the specimen broke and failed. SEM observed the fracture surface of the sample, and the failure modes at different temperatures were obtained, explaining why IPSS changes with temperature.</p><h3>Conclusions</h3><p>The improved Iosipescu method is used to measure the high-temperature in-plane shear properties of CMCs and can enable high-temperature in-situ testing.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"683 - 697"},"PeriodicalIF":2.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074126","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":"Plasticity Bridges Microscale Martensitic Shear Bands in Superelastic Nitinol","authors":"A. Christison,&nbsp;H. M. Paranjape,&nbsp;S. Daly","doi":"10.1007/s11340-025-01161-6","DOIUrl":"10.1007/s11340-025-01161-6","url":null,"abstract":"<div><h3>Background</h3><p>Superelastic shape memory alloys (SMAs) such as nickel-titanium, also known as Nitinol, recover large deformations via a reversible, stress-induced martensitic transformation.</p><h3>Objective</h3><p>Partitioning the deformation into the contributions from superelasticity and plasticity and quantifying the interaction between these mechanisms is key to modeling their fatigue behavior.</p><h3>Methods</h3><p>We capture these microscopic interactions across many grains using a combination of scanning electron microscopy digital image correlation (SEM-DIC) and electron backscatter diffraction (EBSD). Modeling our data as a statistical distribution, we employ a Gaussian Mixture Model (GMM) soft clustering framework to understand how these mechanisms interact and evolve as a function of global strain.</p><h3>Results</h3><p>Our findings show that, under globally-applied uniaxial tensile loading, plasticity bridges deformation in regions where competing positive and negative martensitic shear bands intersect. Early stage transformation-induced plasticity is concentrated at these intersections and forms concurrently with the Lüders-like martensitic transformation front, often appearing with a zig-zag pattern that is linked to compound twinning at the martensite-martensite interface. At higher strains, austenite slip is activated as a second mechanism of plastic deformation.</p><h3>Conclusions</h3><p>We propose that this plastic bridging mechanism underpins the prestrain effects previously reported in the literature, where higher prestrains can enhance the fatigue strength of superelastic materials within a given loading mode.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"699 - 716"},"PeriodicalIF":2.0,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01161-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074125","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":"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":"Dynamic Mechanical Behavior of Sinusoidal Corrugated Dual-Phase Lattice Metamaterials by Additive Manufacturing","authors":"H. Wang,&nbsp;J. You,&nbsp;Y. Tian,&nbsp;Z. Chen,&nbsp;S. Yin","doi":"10.1007/s11340-025-01160-7","DOIUrl":"10.1007/s11340-025-01160-7","url":null,"abstract":"<div><h3>Background</h3><p>Additive manufacturing enables lattice metamaterials designed with complex architectures. However, how to design the architecture for greater impact resistance remains not fully explored.</p><h3>Objective</h3><p>This study aims to develop bio-inspired dual-phase metamaterials and examine their dynamic performance.</p><h3>Methods</h3><p>By mimicking the impact region of mantis shrimp, dual-phase lattices (DPLs) were designed by incorporating reinforcement phase (RP) as sinusoidal corrugated forms with multiple phase differences. Then, those metamaterial composites were fabricated using additive manufacturing techniques with stainless steel powder and compressed under different strain rates.</p><h3>Results</h3><p>Under quasi-static compression conditions, DPLs demonstrated superior energy absorption capacity compared to traditional homogeneous lattice materials. For DPLs with various phase architectures, the differences in load-bearing capacity, failure modes, and impact energy dissipation time became more pronounced as strain rate increased. The dual-phase lattice metamaterials showed 2.83 times greater strength values under low-speed impact conditions than those under quasi-static compression, demonstrating excellent strain-rate hardening effects. Failure modes were found to be associated with both RP arrangement patterns and compressive strain rates. However, the shear band propagation paths under low-speed impact were consistent with those observed under quasi-static compression, indicating that RP pattern governed the shear band distribution irrespective of impact velocity.</p><h3>Conclusions</h3><p>This work provided valuable insights for the architecture design of lattice metamaterials in dynamic application.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 4","pages":"541 - 551"},"PeriodicalIF":2.0,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143918963","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":"Development of Kolsky Tension Bar Based Dynamic Incremental Strain and Singular Strain Loading Capability","authors":"B. Song,&nbsp;T. Martinez,&nbsp;A. Y. Ku,&nbsp;J. Deitz,&nbsp;P. Noell","doi":"10.1007/s11340-025-01159-0","DOIUrl":"10.1007/s11340-025-01159-0","url":null,"abstract":"<div><h3>Background</h3><p>The multiple loadings in a conventional Kolsky bar test prevent an in-depth understanding of the relationship between microstructure change and load history under dynamic loading.</p><h3>Objective</h3><p>In order to correlate the microstructural changes to the dynamic load history, it is necessary to develop a new dynamic test capability that allows the specimen be incrementally deformed with a singular loading for each strain increment.</p><h3>Methods</h3><p>A dynamic incremental strain and singular strain loading (DI <span>(epsilon)</span> S<i>ϵ</i>L) capability based on Kolsky tension bar technique was developed. Different design options and considerations are presented to facilitate the DI <span>(epsilon)</span> S<i>ϵ</i>L capability such that the user can choose the combination that best meets their test requirements.</p><h3>Results</h3><p>To demonstrate the new capability, a dog-bone shaped 316L stainless steel was subjected to a series of dynamic tensile loadings with an incremental strain of ~ 11% for each singular loading test. The 316L stainless steel specimens were subjected to a singular loading but different strains under adiabatic condition. At the same dynamic strain rate, the 316L stainless steel became softer and less ductile under adiabatic condition due to adiabatic heating.</p><h3>Conclusions</h3><p>With this new capability, one could decouple the thermosoftening from a conventional dynamic tension test for predictive rate-dependent material model development. The information obtained from this capability may also be used to determine microstructural change and/or damage evolution during dynamic tension testing.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"667 - 681"},"PeriodicalIF":2.0,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073738","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":"Performance Analysis of Digital Camera in DIC: Physical Parameters, Noise, and Bit-Depths","authors":"A. Haghighi,&nbsp;N. Soltani,&nbsp;H. Asemani","doi":"10.1007/s11340-025-01157-2","DOIUrl":"10.1007/s11340-025-01157-2","url":null,"abstract":"<div><h3>Background</h3><p>The accuracy of Digital Image Correlation is considerably influenced by the quality of images taken from the specimen surface. While previous have examined the impact of camera parameters on DIC results, the relationship between camera characteristics and DIC errors remains unclear.</p><h3>Objective</h3><p>In this study, a new theoretical model is introduced to estimate the DIC errors sourced from the camera.</p><h3>Methods</h3><p>The model is derived from the EMVA 1288 standard and contains camera gain, bit depth, and noise error. To validate the model, its results were compared with the real errors calculated from DIC results, and to determine the accurate error, various noise and gains effects were applied to digital images and then displacement and strain were numerically applied to these manipulated images and original images. The error calculated from the DIC successfully matched the error estimated by the model, proving the applicability of the models.</p><h3>Results</h3><p>The individual effects of noise, camera gain, and bit depth are analyzed separately, exploring their respective influences on the DIC. Subsequently, a simple formula is proposed to express camera performance in DIC.</p><h3>Conclusions</h3><p>Results showed that the DIC accuracy is considerably influenced by the camera gain, and temporal dark noise has a notable impact on DIC accuracy, particularly in scenarios with low-contrast speckle patterns. However, the influence of bit depth is negligible.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"653 - 666"},"PeriodicalIF":2.0,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073923","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":"Shape Function-Based Strain Determination in DIC for Solids and Lattice Structures","authors":"M. Hofmann,&nbsp;M. Greiner,&nbsp;M. Klein,&nbsp;M. Oechsner,&nbsp;C. Mittelstedt","doi":"10.1007/s11340-025-01155-4","DOIUrl":"10.1007/s11340-025-01155-4","url":null,"abstract":"<div><h3>Background</h3><p>Additive Manufacturing offers the opportunity to build lattice structures with benefits in manufacturing efficiency and weight. For the determination of the fatigue properties of lattice structures, it lacks a method to determine the deformation under mechanic stress.</p><h3>Objective</h3><p>A digital image correlation (DIC) algorithm was implemented. The algorithm determines strains within a subset in an uncommon way by physically interpreting the subset shape function and does not need neighboring subsets, therefore.</p><h3>Method</h3><p>With a monochrome background this shape function-based strain determination is able to determine the deformation of a whole lattice unit cell, even if the background is visible in sectors of the subset. The implementation is validated by comparing the results in quasi-static tests on bulk material specimens to the results tactile sensors and a conventional DIC program. Then the deformation of lattice unit cells in fatigue tests is evaluated.</p><h3>Results</h3><p>The shape function-based strain determination performs well in quasi-static tests even for large deformations. The deformation of lattice unit cells is determined successfully, whereby conventional DIC algorithms can be challenged if the lattice’s strut diameter becomes close to the image resolution. The determined strains are appropriate for lifetime prediction and fractures can be detected.</p><h3>Conclusion</h3><p>The shape function-based strain determination is a suitable tool for determination of large local strains as well as strains in lattice structures, which do partially not cover the background in the whole region of interest due to periodic empty spaces between the lattice struts. For determination of strain fields, conventional DIC algorithms will still be more efficient in this state of development.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"637 - 652"},"PeriodicalIF":2.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01155-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073587","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}