Pub Date : 2025-03-14DOI: 10.1007/s11340-025-01171-4
Y. Shen, X. Wang, W. Yang, H. Wang, D. Shu
Background
The adiabatic temperature increase at high strain rates can affect the martensitic phase transformation, but the strain rate itself may also play an important role in determining the rate of phase transformation. To date, no systematic work has been carried out to investigate and isolate the effects of strain rate and adiabatic heating on the deformation-induced α′-martensite transformation.
Objective
Uncoupling the effects of high strain rate and adiabatic heating on strain induced martensitic phase transformations in a metastable austenitic steel.
Methods
Strain incremental experiments were carried out with a designed strain control fixture to assess the effect of strain rate effects on phase transitions. The effect of adiabatic heating of the specimens on the phase transformation is assessed by comparing interrupted and incremental tests.
Results
The results of the strain increment experiments indicate that the increase in strain rate has an inhibitory effect on the phase transformation. Comparing the interrupted and incremental tests, the results show that the adiabatic temperature rise inhibits the phase transformation of martensite.
Conclusion
The decoupling of the strain rate and adiabatic temperature increase on α′-martensite transformation was successfully realized by effectively reducing the adiabatic temperature rise of the samples by adopting the strain increment test method during the high strain rate application process.
{"title":"Uncoupling the Effects of High Strain Rate and Adiabatic Heating on Strain Induced Martensitic Phase Transformations in a Metastable Austenitic Steel","authors":"Y. Shen, X. Wang, W. Yang, H. Wang, D. Shu","doi":"10.1007/s11340-025-01171-4","DOIUrl":"10.1007/s11340-025-01171-4","url":null,"abstract":"<div><h3>Background</h3><p>The adiabatic temperature increase at high strain rates can affect the martensitic phase transformation, but the strain rate itself may also play an important role in determining the rate of phase transformation. To date, no systematic work has been carried out to investigate and isolate the effects of strain rate and adiabatic heating on the deformation-induced α′-martensite transformation.</p><h3>Objective</h3><p>Uncoupling the effects of high strain rate and adiabatic heating on strain induced martensitic phase transformations in a metastable austenitic steel.</p><h3>Methods</h3><p>Strain incremental experiments were carried out with a designed strain control fixture to assess the effect of strain rate effects on phase transitions. The effect of adiabatic heating of the specimens on the phase transformation is assessed by comparing interrupted and incremental tests.</p><h3>Results</h3><p>The results of the strain increment experiments indicate that the increase in strain rate has an inhibitory effect on the phase transformation. Comparing the interrupted and incremental tests, the results show that the adiabatic temperature rise inhibits the phase transformation of martensite.</p><h3>Conclusion</h3><p>The decoupling of the strain rate and adiabatic temperature increase on α′-martensite transformation was successfully realized by effectively reducing the adiabatic temperature rise of the samples by adopting the strain increment test method during the high strain rate application process.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 6","pages":"835 - 843"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165706","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}
Pub Date : 2025-03-14DOI: 10.1007/s11340-025-01170-5
B. Liu, X. Zheng, L.R. Xu
Background
The shear strength of an engineering material is a critical mechanical parameter, however, its measurement often encounters challenges especially for new materials. Moreover, little research was conducted on the size effect of the shear strengths.
Objective
This study is to determine the specimen thickness effect on the interlayer shear strengths of two types of additively manufactured polymers.
Methods
A combined experimental and numerical investigation of the interlayer shear strength measurement was conducted, and its application targeted polylactic acid and polyamide using fused filament fabrication and selective laser sintering, respectively. A necking-shaped shear specimen was proposed to measure the interlayer shear strengths with the aid of both 3D finite element analysis and 3D digital image correlation.
Results
All specimens showed a consistent pure shear fracture pattern, and the shear strengths increased as the specimen thickness increased.
Conclusions
Future interlayer shear strength measurements should specify a fixed specimen thickness for fair comparisons.
{"title":"Influence of the Specimen Thickness on the Interlayer Shear Strengths of Additively Manufactured Polymers","authors":"B. Liu, X. Zheng, L.R. Xu","doi":"10.1007/s11340-025-01170-5","DOIUrl":"10.1007/s11340-025-01170-5","url":null,"abstract":"<div><h3>Background</h3><p>The shear strength of an engineering material is a critical mechanical parameter, however, its measurement often encounters challenges especially for new materials. Moreover, little research was conducted on the size effect of the shear strengths.</p><h3>Objective</h3><p>This study is to determine the specimen thickness effect on the interlayer shear strengths of two types of additively manufactured polymers.</p><h3>Methods</h3><p>A combined experimental and numerical investigation of the interlayer shear strength measurement was conducted, and its application targeted polylactic acid and polyamide using fused filament fabrication and selective laser sintering, respectively. A necking-shaped shear specimen was proposed to measure the interlayer shear strengths with the aid of both 3D finite element analysis and 3D digital image correlation.</p><h3>Results</h3><p>All specimens showed a consistent pure shear fracture pattern, and the shear strengths increased as the specimen thickness increased.</p><h3>Conclusions</h3><p>Future interlayer shear strength measurements should specify a fixed specimen thickness for fair comparisons.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 4","pages":"597 - 602"},"PeriodicalIF":2.0,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143919062","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}
Pub Date : 2025-03-14DOI: 10.1007/s11340-025-01165-2
J. Cai, K.C.H. Chin, A. Gupta, A.J. Boydston, R. Thevamaran
Background
Creating structural materials with mesoscale architectures and functional gradients facilitates the synergistic achievement of outstanding strength, stiffness, and damping, which is essential for effectively mitigating extreme mechanical waves and vibrations. In contrast to conventional stochastic foams, deterministic architected materials fabricated by three-dimensional (3D) printing, such as minimal surface-based gyroid lattices, offer a broad design space to achieve exceptional mechanical performance with efficient material utilization.
Objective
Using 3D printed elastomeric gyroid lattices as a model cellular material system, this work focuses on studying the quasi-static and dynamic mechanical behavior of soft gyroid lattices made from viscoelastic elastomeric materials, as well as the effects of incorporating pre-compressive strain as a strategy to tailor the dynamic performance of gradient gyroid lattices.
Methods
Soft gyroid structures based on viscoelastic elastomeric polymer were 3D printed by stereolithography (SLA). We performed quasi-static compression up to 70% strain to study the mechanical behavior and energy absorption performance of the 3D printed gyroid lattices. Dynamic mechanical analyses in compression mode at different applied static precompressions were conducted to understand the effects of structural gradients on dynamic material properties.
Results
We show that the integration of viscoelastic elastomeric material with gradient architecting—compared with uniform periodic lattices—leads to superior independent control over dynamic material properties. Under harmonic excitations, by leveraging the structural gradient of the gyroid lattice with applied static precompression, we demonstrate a greater tunability of dynamic stiffness in graded-gyroids compared with the uniform gyroid structure. In graded-gyroids, we achieve a substantial enhancement in dynamic stiffness (over 600%) while maintaining the inherent damping capabilities, thus overcoming the common trade-off between stiffness and damping seen in engineering materials.
Conclusion
Our study shows the potential of 3D printed architected cellular structures with tailored structural gradients as advanced lightweight structural materials for extreme damping, shock-absorbing, and robust robotic material applications.
{"title":"Overcoming Dynamic Stiffness-Damping Trade-Off with Structural Gradients in 3D Printed Elastomeric Gyroid Lattices","authors":"J. Cai, K.C.H. Chin, A. Gupta, A.J. Boydston, R. Thevamaran","doi":"10.1007/s11340-025-01165-2","DOIUrl":"10.1007/s11340-025-01165-2","url":null,"abstract":"<div><h3>Background</h3><p>Creating structural materials with mesoscale architectures and functional gradients facilitates the synergistic achievement of outstanding strength, stiffness, and damping, which is essential for effectively mitigating extreme mechanical waves and vibrations. In contrast to conventional stochastic foams, deterministic architected materials fabricated by three-dimensional (3D) printing, such as minimal surface-based gyroid lattices, offer a broad design space to achieve exceptional mechanical performance with efficient material utilization.</p><h3>Objective</h3><p>Using 3D printed elastomeric gyroid lattices as a model cellular material system, this work focuses on studying the quasi-static and dynamic mechanical behavior of soft gyroid lattices made from viscoelastic elastomeric materials, as well as the effects of incorporating pre-compressive strain as a strategy to tailor the dynamic performance of gradient gyroid lattices.</p><h3>Methods</h3><p>Soft gyroid structures based on viscoelastic elastomeric polymer were 3D printed by stereolithography (SLA). We performed quasi-static compression up to 70% strain to study the mechanical behavior and energy absorption performance of the 3D printed gyroid lattices. Dynamic mechanical analyses in compression mode at different applied static precompressions were conducted to understand the effects of structural gradients on dynamic material properties.</p><h3>Results</h3><p>We show that the integration of viscoelastic elastomeric material with gradient architecting—compared with uniform periodic lattices—leads to superior independent control over dynamic material properties. Under harmonic excitations, by leveraging the structural gradient of the gyroid lattice with applied static precompression, we demonstrate a greater tunability of dynamic stiffness in graded-gyroids compared with the uniform gyroid structure. In graded-gyroids, we achieve a substantial enhancement in dynamic stiffness (over 600%) while maintaining the inherent damping capabilities, thus overcoming the common trade-off between stiffness and damping seen in engineering materials.</p><h3>Conclusion</h3><p>Our study shows the potential of 3D printed architected cellular structures with tailored structural gradients as advanced lightweight structural materials for extreme damping, shock-absorbing, and robust robotic material applications.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 6","pages":"821 - 834"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165994","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}
Pub Date : 2025-03-14DOI: 10.1007/s11340-025-01164-3
A. Edwards, J. Cho, H. Tippur
Background
Over-deterministic least-squares methods of extracting SIFs from measured full-field quantities in conjunction with asymptotic fields has been the mainstay of experimental fracture mechanics. The vision-based methods of Digital Image Correlation (DIC) to determine displacements and Digital Gradient Sensing (DGS) to determine stress gradients have played an important role in this regard.
Objectives
In DIC and DGS, two or more orthogonal fields are measured simultaneously. Yet, while extracting SIFs, often only one of the components is picked based on intuition/legacy. This could result in erroneous SIF values under mixed-mode conditions.
Methods
Robustness of SIF extraction by utilizing all components in tandem is demonstrated over a wide range of pure- and mixed-mode conditions. An edge-notched semi-circular specimen geometry is used to create different mode-mixities. The data from DIC and DGS are processed using both the combined fields and legacy approaches. The accuracy and robustness of the former relative to the latter is demonstrated for (a) different number of higher order terms in the asymptotic series, (b) crack tip location uncertainty, and (c) different regions of data extraction.
Results
An order of magnitude reduction in standard deviation and root-mean-squared error in mixed and pure mode SIFs are seen for DIC and the combined fields method. Marginal improvements are seen when the crack tip position or the region of interest are varied in DGS.
Conclusions
Robustness of extracting mixed-mode SIFs accurately by employing all measured fields concurrently in an over-deterministic least-squares approach is superior to using a single component based on intuition/legacy.
{"title":"Extracting Mixed-Mode Fracture Parameters Using Two Vision-based Methods: Comparison of Combined Fields Method with Legacy Approach","authors":"A. Edwards, J. Cho, H. Tippur","doi":"10.1007/s11340-025-01164-3","DOIUrl":"10.1007/s11340-025-01164-3","url":null,"abstract":"<div><h3>Background</h3><p>Over-deterministic least-squares methods of extracting SIFs from measured full-field quantities in conjunction with asymptotic fields has been the mainstay of experimental fracture mechanics. The vision-based methods of Digital Image Correlation (DIC) to determine displacements and Digital Gradient Sensing (DGS) to determine stress gradients have played an important role in this regard.</p><h3>Objectives</h3><p>In DIC and DGS, two or more orthogonal fields are measured simultaneously. Yet, while extracting SIFs, often only one of the components is picked based on intuition/legacy. This could result in erroneous SIF values under mixed-mode conditions.</p><h3>Methods</h3><p>Robustness of SIF extraction by utilizing all components in tandem is demonstrated over a wide range of pure- and mixed-mode conditions. An edge-notched semi-circular specimen geometry is used to create different mode-mixities. The data from DIC and DGS are processed using both the combined fields and legacy approaches. The accuracy and robustness of the former relative to the latter is demonstrated for (a) different number of higher order terms in the asymptotic series, (b) crack tip location uncertainty, and (c) different regions of data extraction.</p><h3>Results</h3><p>An order of magnitude reduction in standard deviation and root-mean-squared error in mixed and pure mode SIFs are seen for DIC and the combined fields method. Marginal improvements are seen when the crack tip position or the region of interest are varied in DGS.</p><h3>Conclusions</h3><p>Robustness of extracting mixed-mode SIFs accurately by employing all measured fields concurrently in an over-deterministic least-squares approach is superior to using a single component based on intuition/legacy.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 6","pages":"845 - 868"},"PeriodicalIF":2.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145165995","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}
Pub Date : 2025-03-12DOI: 10.1007/s11340-025-01168-z
M. Gonçalves, S. Thuillier, A. Andrade-Campos
Background
Numerical simulation is becoming essential in the mechanical design of sheet metal components, requiring advanced material models, composed of many unknown parameters, to accurately describe complex material behavior. Traditionally, these parameters are identified through multiple quasi-homogeneous tests, each providing specific mechanical data on a particular strain state. The emergence of heterogeneous mechanical tests has revolutionized this process by enabling the capture of a wide range of strain states in a single experiment.
Objective
This study focuses on the experimental analysis of three heterogeneous mechanical tests, previously studied numerically. The main objective is to confirm the quality and relevance of the mechanical deformation observed when using real data and evaluate the sensitivity of these tests to different high-strength steels.
Methods
Uniaxial loading tests were conducted on three different specimen designs, using Stereo Digital Image Correlation to capture the mechanical fields on the surface. Multi-DIC systems were used to measure the out-of-plane behavior observed for a specimen design to increase the strain richness provided by the test. The repeatability of these tests is checked due to their complex designs.
Results
The results show that the potential of heterogeneous mechanical tests remains unchanged when tested in real-world experimental settings.
Conclusions
When combined with full-field measurement techniques, these can provide a wide range of mechanical behavior data from a single test, reducing the number of tests needed for advanced material characterization.
{"title":"Assessing the Potential of Heterogeneous Mechanical Tests for Sheet Metals Through Experimentally Measured Full-Fields","authors":"M. Gonçalves, S. Thuillier, A. Andrade-Campos","doi":"10.1007/s11340-025-01168-z","DOIUrl":"10.1007/s11340-025-01168-z","url":null,"abstract":"<div><h3>Background</h3><p>Numerical simulation is becoming essential in the mechanical design of sheet metal components, requiring advanced material models, composed of many unknown parameters, to accurately describe complex material behavior. Traditionally, these parameters are identified through multiple quasi-homogeneous tests, each providing specific mechanical data on a particular strain state. The emergence of heterogeneous mechanical tests has revolutionized this process by enabling the capture of a wide range of strain states in a single experiment.</p><h3>Objective</h3><p>This study focuses on the experimental analysis of three heterogeneous mechanical tests, previously studied numerically. The main objective is to confirm the quality and relevance of the mechanical deformation observed when using real data and evaluate the sensitivity of these tests to different high-strength steels.</p><h3>Methods</h3><p>Uniaxial loading tests were conducted on three different specimen designs, using Stereo Digital Image Correlation to capture the mechanical fields on the surface. Multi-DIC systems were used to measure the out-of-plane behavior observed for a specimen design to increase the strain richness provided by the test. The repeatability of these tests is checked due to their complex designs.</p><h3>Results</h3><p>The results show that the potential of heterogeneous mechanical tests remains unchanged when tested in real-world experimental settings.</p><h3>Conclusions</h3><p>When combined with full-field measurement techniques, these can provide a wide range of mechanical behavior data from a single test, reducing the number of tests needed for advanced material characterization.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"757 - 774"},"PeriodicalIF":2.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01168-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074146","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}
Pub Date : 2025-03-12DOI: 10.1007/s11340-025-01166-1
S. Langlois, F. Benboudjema, M. Maaroufi, F. Hafid, B. Smaniotto, F. Hild, A. Fau
Background
Debonding between a cementitious material and a reinforcement is a mechanical phenomenon of great interest. It cannot be quantified directly through standard tests since it occurs within the material bulk.
Objective
The goal is to develop an experimental method for quantifying debonding during in-situ pull-out tests that also induce damage in the mortar matrix.
Method
A 1/50 scale foundation model is subjected to a pull-out test in an X-ray tomograph. A finite-element-based Digital Volume Correlation analysis with mechanical regularization is conducted based on a three-dimensional mesh constructed to reproduce the geometry of the foundation and reinforcement.
Results
Heterogeneous regularization with a single-node mesh has little effect on the correlation residuals. Using split nodes to describe the interface drastically reduces the correlation residuals in the reinforcement. If cracking occurs in addition to debonding, introducing a heterogeneous regularization based on damaged elements improves the quantification of debonding.
Conclusion
By splitting the nodes at the interface and localizing regularization in damaged elements, the reinforcement and mortar kinematics is better captured and thus debonding as well.
{"title":"Quantification of Reinforcement Debonding in Damaged Mortar via Digital Volume Correlation","authors":"S. Langlois, F. Benboudjema, M. Maaroufi, F. Hafid, B. Smaniotto, F. Hild, A. Fau","doi":"10.1007/s11340-025-01166-1","DOIUrl":"10.1007/s11340-025-01166-1","url":null,"abstract":"<div><h3>Background</h3><p>Debonding between a cementitious material and a reinforcement is a mechanical phenomenon of great interest. It cannot be quantified directly through standard tests since it occurs within the material bulk.</p><h3>Objective</h3><p>The goal is to develop an experimental method for quantifying debonding during <i>in-situ</i> pull-out tests that also induce damage in the mortar matrix.</p><h3>Method</h3><p>A 1/50 scale foundation model is subjected to a pull-out test in an X-ray tomograph. A finite-element-based Digital Volume Correlation analysis with mechanical regularization is conducted based on a three-dimensional mesh constructed to reproduce the geometry of the foundation and reinforcement.</p><h3>Results</h3><p>Heterogeneous regularization with a single-node mesh has little effect on the correlation residuals. Using split nodes to describe the interface drastically reduces the correlation residuals in the reinforcement. If cracking occurs in addition to debonding, introducing a heterogeneous regularization based on damaged elements improves the quantification of debonding.</p><h3>Conclusion</h3><p>By splitting the nodes at the interface and localizing regularization in damaged elements, the reinforcement and mortar kinematics is better captured and thus debonding as well.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"799 - 817"},"PeriodicalIF":2.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11340-025-01166-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074145","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}
Pub Date : 2025-03-12DOI: 10.1007/s11340-025-01169-y
Y. Ai, J. Shang, Y. Gong, S. Liu
Background
The in situ mechanical measurement of nanomaterials using microelectromechanical system accessories in electron microscopy has attracted considerable interest because of its ability to combine microstructure responses and stress conditions.
Objective
In this study, an in situ large-deflection longitudinal‒transverse bending measurement technique was developed in a double-cantilever beam system using transmission electron microscopy (TEM).
Methods
Nonlinear large-strain bending tests of raw and high-temperature-oxidized 3C-silicon carbide (3C-SiC) nanowires (NWs) were performed using TEM. After an explicit polynomial–trigonometric combined-function (P‒T model) was introduced to fit the NW contour in each image frame, a mechanical algorithm based on the fitting curve was proposed to calculate the stress and strain in batches.
Results
Contour modeling analysis using the P‒T model revealed brittle fracture in a 104-nm-diameter SiC NW with a fracture strain of 3.46% and a modulus of 590.8 GPa. Plastic deformation occurred during the bending of a 430-nm-diameter oxidized core–shell SiC-SiO2 NW, with a fracture strain exceeding 7.07% and a modulus of 42.6 GPa.
Conclusion
Compared with results from other widely used approximation fitting models, the measurement results based on the P‒T method were more accurate and stable. The modulus reduction and brittle‒ductile transition induced by the amorphous oxide layer on the SiC core were demonstrated using the P‒T method.
利用电子显微镜中的微机电系统附件对纳米材料进行原位力学测量，由于其结合微观结构响应和应力条件的能力而引起了人们的广泛关注。目的建立双悬臂梁系统大挠度纵向-横向弯曲的透射电镜原位测量技术。方法采用透射电镜对未加工的和高温氧化的3c -碳化硅纳米线进行了非线性大应变弯曲试验。在引入显式多项式-三角组合函数（P-T模型）对每帧图像的NW轮廓进行拟合后，提出了基于拟合曲线的力学算法来批量计算应力和应变。结果采用P-T模型进行等高线建模分析，发现104 nm SiC NW的脆性断裂，断裂应变为3.46%，模量为590.8 GPa。430 nm直径氧化核壳SiC-SiO2 NW在弯曲过程中发生塑性变形，断裂应变超过7.07%，模量为42.6 GPa。结论与其他常用的近似拟合模型相比，基于P-T法的测量结果更准确、更稳定。用P-T法证明了SiC芯上非晶氧化层诱导的模量降低和脆-韧转变。
{"title":"Development of a P‒T-Model-Based In-Situ Bending Measurement Method for Nanowires: Addressing Mechanical Challenges in High-Precision Experiments","authors":"Y. Ai, J. Shang, Y. Gong, S. Liu","doi":"10.1007/s11340-025-01169-y","DOIUrl":"10.1007/s11340-025-01169-y","url":null,"abstract":"<div><h3>Background</h3><p>The <i>in situ</i> mechanical measurement of nanomaterials using microelectromechanical system accessories in electron microscopy has attracted considerable interest because of its ability to combine microstructure responses and stress conditions.</p><h3>Objective</h3><p>In this study, an <i>in situ</i> large-deflection longitudinal‒transverse bending measurement technique was developed in a double-cantilever beam system using transmission electron microscopy (TEM).</p><h3>Methods</h3><p>Nonlinear large-strain bending tests of raw and high-temperature-oxidized 3C-silicon carbide (3C-SiC) nanowires (NWs) were performed using TEM. After an explicit polynomial–trigonometric combined-function (P‒T model) was introduced to fit the NW contour in each image frame, a mechanical algorithm based on the fitting curve was proposed to calculate the stress and strain in batches.</p><h3>Results</h3><p>Contour modeling analysis using the P‒T model revealed brittle fracture in a 104-nm-diameter SiC NW with a fracture strain of 3.46% and a modulus of 590.8 GPa. Plastic deformation occurred during the bending of a 430-nm-diameter oxidized core–shell SiC-SiO<sub>2</sub> NW, with a fracture strain exceeding 7.07% and a modulus of 42.6 GPa.</p><h3>Conclusion</h3><p>Compared with results from other widely used approximation fitting models, the measurement results based on the P‒T method were more accurate and stable. The modulus reduction and brittle‒ductile transition induced by the amorphous oxide layer on the SiC core were demonstrated using the P‒T method.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"775 - 798"},"PeriodicalIF":2.0,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144074147","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}
Pub Date : 2025-03-10DOI: 10.1007/s11340-025-01167-0
K. Goyal, C. Singh, G. Subhash
Background
The current ASTM formulation for determining dynamic ring-on-ring test method is applicable for thick plates and is not suitable for thin plates that can undergo large flexural deformation where membrane stresses dominate.
Objective
The objective is to design and develop a new dynamic ring-on-ring test method with the ability to accurately measure load and visually access the tensile surface of a specimen for tracking failure. It is also aimed to develop a scientifically robust test procedure and analysis method to validate this new design for obtaining accurate biaxial flexural strength of thin flexible plates.
Methods
A unique load-cell assembly that houses a doughnut-shaped loadcell and capable of preloading the loadcell to a desired force level while simultaneously providing an unobstructed line-of-sight for a high-speed camera to capture the evolving damage modes in the specimen is developed. This loadcell assembly is used in a Hopkinson bar setup to test thin glass specimens and determine their dynamic biaxial flexural fracture strength. A new calibration procedure is proposed that accounts for the delay in the force sensed by the loadcell and provides a more accurate measure of the applied dynamic load on the specimen surface. An analysis method that accounts for membrane stresses under axisymmetric loading is developed to determine the biaxial failure strength of thin glass specimens that undergo large flexural deformation.
Results
A loadcell calibration method, an experimental procedure to dynamically test thin flexible specimens, and an analysis method that accounts for membrane stresses were developed. The Experimental results for three types of thin transparent materials reveal that the dynamic flexural failure strength is 40% more than their corresponding quasistatic strength. Radial cracks evolve from a preexisting defect during the biaxial loading and the damage growth rate was determined to be 1570 m/s.
Conclusions
The results reveal that the formulation suggested by the ASTM standard overpredicts the failure strength of thin glass specimen by several times the strength determined by the developed analytical method that accounts for the membrane stress. The analysis procedure provides a repeatable measurement of dynamic biaxial failure strength of flexible thin plates.
{"title":"A Novel Approach to Dynamic Equi-Biaxial Testing of Thin Flexible Materials Using the Ring-on-Ring Test Method","authors":"K. Goyal, C. Singh, G. Subhash","doi":"10.1007/s11340-025-01167-0","DOIUrl":"10.1007/s11340-025-01167-0","url":null,"abstract":"<div><h3>Background</h3><p>The current ASTM formulation for determining dynamic ring-on-ring test method is applicable for thick plates and is not suitable for thin plates that can undergo large flexural deformation where membrane stresses dominate.</p><h3>Objective</h3><p>The objective is to design and develop a new dynamic ring-on-ring test method with the ability to accurately measure load and visually access the tensile surface of a specimen for tracking failure. It is also aimed to develop a scientifically robust test procedure and analysis method to validate this new design for obtaining accurate biaxial flexural strength of thin flexible plates.</p><h3>Methods</h3><p>A unique load-cell assembly that houses a doughnut-shaped loadcell and capable of preloading the loadcell to a desired force level while simultaneously providing an unobstructed line-of-sight for a high-speed camera to capture the evolving damage modes in the specimen is developed. This loadcell assembly is used in a Hopkinson bar setup to test thin glass specimens and determine their dynamic biaxial flexural fracture strength. A new calibration procedure is proposed that accounts for the delay in the force sensed by the loadcell and provides a more accurate measure of the applied dynamic load on the specimen surface. An analysis method that accounts for membrane stresses under axisymmetric loading is developed to determine the biaxial failure strength of thin glass specimens that undergo large flexural deformation.</p><h3>Results</h3><p>A loadcell calibration method, an experimental procedure to dynamically test thin flexible specimens, and an analysis method that accounts for membrane stresses were developed. The Experimental results for three types of thin transparent materials reveal that the dynamic flexural failure strength is 40% more than their corresponding quasistatic strength. Radial cracks evolve from a preexisting defect during the biaxial loading and the damage growth rate was determined to be 1570 m/s.</p><h3>Conclusions</h3><p>The results reveal that the formulation suggested by the ASTM standard overpredicts the failure strength of thin glass specimen by several times the strength determined by the developed analytical method that accounts for the membrane stress. The analysis procedure provides a repeatable measurement of dynamic biaxial failure strength of flexible thin plates.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"65 5","pages":"743 - 756"},"PeriodicalIF":2.0,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144073845","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}
Pub Date : 2025-03-03DOI: 10.1007/s11340-025-01158-1
K.M. Fitzgerald, W. Gilliland, H. Lim, T. Ruggles, N. Aragon, J.D. Carroll
Background
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.
Objective
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.
Methods
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.
Results
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.
Conclusions
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.
{"title":"Microstructure Clones","authors":"K.M. Fitzgerald, W. Gilliland, H. Lim, T. Ruggles, N. Aragon, 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}
Pub Date : 2025-02-28DOI: 10.1007/s11340-025-01156-3
S. Wu, W. Li, L. Zhuo, J. Zhu, G. Xie, W. Zhang, P. Singhatanadgid, D. Zhang
Background
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.
Objective
A suitable method was developed for simultaneously measuring stress–strain and adiabatic temperature for polycarbonate subjected to slow torsion (< 1 s−1).
Methods
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.
Results
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.
Conclusions
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.
{"title":"Thermodynamic Investigation of Glassy Polycarbonate Under Slow Torsion by Experimentally Characterizing Adiabatic Temperature Rise","authors":"S. Wu, W. Li, L. Zhuo, J. Zhu, G. Xie, W. Zhang, P. Singhatanadgid, 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 (< 1 s<sup>−1</sup>).</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}
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