Pub Date : 2024-07-31DOI: 10.1007/s11340-024-01100-x
{"title":"On the Cover: Operando Characterizations of Lithium Penetration-Induced Fracture in Solid Electrolytes by M. Lu, S. Xia","authors":"","doi":"10.1007/s11340-024-01100-x","DOIUrl":"10.1007/s11340-024-01100-x","url":null,"abstract":"","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 7","pages":"969 - 969"},"PeriodicalIF":2.0,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141872715","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 : 2024-07-11DOI: 10.1007/s11340-024-01087-5
Y. X. Luo, Y. L. Dong, F. Q. Yang, X. Y. Lu
Background
In the mechanical testing of high-temperature structural materials, ultra-high temperature deformation measurement is very necessary and very challenging.
Objective
To overcome the challenge of using single-camera stereo-digital image correlation (stereo-DIC) for ultra-high-temperature measurement.
Methods
An ultraviolet single-camera stereo-DIC system combining active UV illuminations, an ultraviolet camera, a single UV narrow bandpass filter, a reflective prism and two reflectors was established. In addition, two types of high temperature speckle patterns were prepared A tensile test of C/C composites at 2600 °C was conducted to verify the effectiveness and accuracy of the developed technology.
Results
The ultraviolet single-camera stereo-DIC system has excellent resistance to thermal radiation. As well, the two types of speckle patterns are available at 2600 °C. And the values of elastic modulus calculated by the developed technology and high-temperature extensometer are very close to each other, and the relative errors are less than 7%.
Conclusions
The well matched strain results with high-temperature extensometer data demonstrates that the ultraviolet single-camera stereo-DIC is an effective ultra-high temperature deformation measurement technology and has great potential in characterizing the deformation response of materials at ultra-high temperatures.
{"title":"Ultraviolet Single-Camera Stereo-Digital Image Correlation for Deformation Measurement up to 2600 °C","authors":"Y. X. Luo, Y. L. Dong, F. Q. Yang, X. Y. Lu","doi":"10.1007/s11340-024-01087-5","DOIUrl":"10.1007/s11340-024-01087-5","url":null,"abstract":"<div><h3>Background</h3><p>In the mechanical testing of high-temperature structural materials, ultra-high temperature deformation measurement is very necessary and very challenging.</p><h3>Objective</h3><p>To overcome the challenge of using single-camera stereo-digital image correlation (stereo-DIC) for ultra-high-temperature measurement.</p><h3>Methods</h3><p>An ultraviolet single-camera stereo-DIC system combining active UV illuminations, an ultraviolet camera, a single UV narrow bandpass filter, a reflective prism and two reflectors was established. In addition, two types of high temperature speckle patterns were prepared A tensile test of C/C composites at 2600 °C was conducted to verify the effectiveness and accuracy of the developed technology.</p><h3>Results</h3><p>The ultraviolet single-camera stereo-DIC system has excellent resistance to thermal radiation. As well, the two types of speckle patterns are available at 2600 °C. And the values of elastic modulus calculated by the developed technology and high-temperature extensometer are very close to each other, and the relative errors are less than 7%.</p><h3>Conclusions</h3><p>The well matched strain results with high-temperature extensometer data demonstrates that the ultraviolet single-camera stereo-DIC is an effective ultra-high temperature deformation measurement technology and has great potential in characterizing the deformation response of materials at ultra-high temperatures.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1343 - 1355"},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141585194","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 : 2024-07-11DOI: 10.1007/s11340-024-01095-5
W.A. Hunnicutt, L.J. Struble, P. Mondal
Background
Modifying the mechanical properties of the solid phase of a porous material, in this study calcium-silicate-hydrate, is frequently possible by changing synthesis conditions, but changes in these conditions can also influence porosity, which in turn may affect the mechanical properties of the porous material. Experimental methods to decouple porosity from the viscoelastic properties of the porous material will aid in optimization of the structure of the solid phase to achieve the desired mechanical properties.
Objective
Explore different nanoindentation techniques in order to determine the viscoelastic properties of the solid phase (without the affect of porosity) of a stiff porous material via experimental methods alone.
Methods
Compacted pellets of calcium-silicate-hydrate were prepared with different porosity and subjected to three nanoindentation techniques to determine viscoelastic behavior and the influence of porosity: dynamic, stress relaxation, and creep. Results of the porosity and of the viscoelastic behavior measurements were analyzed with a reverse-micromechanics model to determine viscoelastic properties of the solid phase, which has not been achieved previously for calcium-silicate-hydrate. These methods can be used in development and refinement of materials to determine how changes in the solid phase (e.g. molecular structure) influence viscoelastic behavior while considering the effect of porosity.
Results
Dynamic nanoindentation was found to be unreliable for the stiff material studied in this work. Normalized stress relaxation and creep data were found to be independent of porosity. Reverse micro-mechanics modeling allowed for characterization of the creep modulus that is consistent with other studies that used computational or synchrotron x-ray methods to characterize mechanical properties of the solid calcium-silicate-hydrate phase.
Conclusion
Creep experiments provide more reliable data than dynamic or stress relaxation experiments. When the porosity is known, reverse-micromechanics modeling can be used determine the creep modulus of the solid phase and thus be used to predict creep modulus of a composite with an arbitrary porosity. If the porosity is not known, the viscoelastic properties of the solid phase can still be compared to each other using a normalized creep modulus that is independent of porosity.
背景改变多孔材料(本研究中为硅酸钙水合物)固相的机械性能通常可以通过改变合成条件来实现,但这些条件的变化也会影响孔隙率,而孔隙率又会影响多孔材料的机械性能。目的探索不同的纳米压痕技术,以便仅通过实验方法确定硬质多孔材料固相的粘弹性能(不受孔隙率的影响)。方法制备具有不同孔隙率的硅酸钙水合物压实颗粒,并采用三种纳米压痕技术确定其粘弹性行为和孔隙率的影响:动态、应力松弛和蠕变。利用反向微观力学模型分析了孔隙率和粘弹性行为的测量结果,从而确定了固相的粘弹性能,这是硅酸钙水合物以前从未实现过的。这些方法可用于开发和改进材料,以确定固相的变化(如分子结构)如何影响粘弹性行为,同时考虑孔隙率的影响。归一化应力松弛和蠕变数据与孔隙率无关。通过反向微观力学建模可以确定蠕变模量的特性,这与其他使用计算或同步辐射 X 射线方法确定固态硅酸钙水合物相的力学特性的研究结果一致。在已知孔隙率的情况下,反向微观力学模型可用于确定固相的蠕变模量,从而用于预测任意孔隙率的复合材料的蠕变模量。如果不知道孔隙率,则仍可使用与孔隙率无关的归一化蠕变模量来比较固相的粘弹性能。
{"title":"Nanoindentation Methods for Viscoelastic Characterization of Stiff Porous Materials","authors":"W.A. Hunnicutt, L.J. Struble, P. Mondal","doi":"10.1007/s11340-024-01095-5","DOIUrl":"10.1007/s11340-024-01095-5","url":null,"abstract":"<div><h3>Background</h3><p>Modifying the mechanical properties of the solid phase of a porous material, in this study calcium-silicate-hydrate, is frequently possible by changing synthesis conditions, but changes in these conditions can also influence porosity, which in turn may affect the mechanical properties of the porous material. Experimental methods to decouple porosity from the viscoelastic properties of the porous material will aid in optimization of the structure of the solid phase to achieve the desired mechanical properties.</p><h3>Objective</h3><p>Explore different nanoindentation techniques in order to determine the viscoelastic properties of the solid phase (without the affect of porosity) of a stiff porous material via experimental methods alone.</p><h3>Methods</h3><p>Compacted pellets of calcium-silicate-hydrate were prepared with different porosity and subjected to three nanoindentation techniques to determine viscoelastic behavior and the influence of porosity: dynamic, stress relaxation, and creep. Results of the porosity and of the viscoelastic behavior measurements were analyzed with a reverse-micromechanics model to determine viscoelastic properties of the solid phase, which has not been achieved previously for calcium-silicate-hydrate. These methods can be used in development and refinement of materials to determine how changes in the solid phase (e.g. molecular structure) influence viscoelastic behavior while considering the effect of porosity.</p><h3>Results</h3><p>Dynamic nanoindentation was found to be unreliable for the stiff material studied in this work. Normalized stress relaxation and creep data were found to be independent of porosity. Reverse micro-mechanics modeling allowed for characterization of the creep modulus that is consistent with other studies that used computational or synchrotron x-ray methods to characterize mechanical properties of the solid calcium-silicate-hydrate phase.</p><h3>Conclusion</h3><p>Creep experiments provide more reliable data than dynamic or stress relaxation experiments. When the porosity is known, reverse-micromechanics modeling can be used determine the creep modulus of the solid phase and thus be used to predict creep modulus of a composite with an arbitrary porosity. If the porosity is not known, the viscoelastic properties of the solid phase can still be compared to each other using a normalized creep modulus that is independent of porosity.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1357 - 1368"},"PeriodicalIF":2.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141585185","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 : 2024-07-09DOI: 10.1007/s11340-024-01089-3
Y.H. Kim, M.K. Kim, J. Suhr, T. Lee, M.K. Kim
Background
Powder bed fusion (PBF) offers enhanced opportunities to manufacture complex components with a high degree of geometric freedom. However, understanding and designing for mechanical properties remains challenging due to numerous factors, such as processing parameters, building direction, and heat treatments.
Objective
In this study, we revealed that the As-built and heat-treated mechanical properties differ from those achieved through traditional manufacturing methods, even when using the same alloy and heat treatments. This phenomenon arises from the intricated microstructures and porosity caused by the repetitive, rapid heating/cooling process involved.
Results
To quantitatively investigate the properties, the conventional heat treatments combining a hot isostatic pressing (HIP), solution, and aging treatment, were conducted on 17-4 PH stainless steel printed in both horizontal and vertical directions. Our findings demonstrate that HIP, coupled with aging treatment, was the most effective method for reducing porosity, and enhancing hardness and yield strength by (56%) and (118%), respectively, while there was a slight decrease in elongation by (5.6%). The high temperature and pressure during HIP enabled the recrystallization of As-built microstructure into lath martensite, and the aging treatment facilitated the production of precipitates to enhance the strength. The solution treatment, however, resulted in poor elongation to (9.3%) while the yield and tensile strength showed similar levels to As-built parts due to insufficient time to recrystallize the As-built microstructure.
Conclusions
We believe these results will offer valuable insights into the manufacturing and post processing not only of PBF 17-4PH stainless steel but also of other alloys.
{"title":"Exploring the Effect of Heat Treatment on the Mechanical Performance of 17-4PH Stainless Steel Specimens Fabricated by Metal Additive Manufacturing","authors":"Y.H. Kim, M.K. Kim, J. Suhr, T. Lee, M.K. Kim","doi":"10.1007/s11340-024-01089-3","DOIUrl":"10.1007/s11340-024-01089-3","url":null,"abstract":"<div><h3>Background</h3><p>Powder bed fusion (PBF) offers enhanced opportunities to manufacture complex components with a high degree of geometric freedom. However, understanding and designing for mechanical properties remains challenging due to numerous factors, such as processing parameters, building direction, and heat treatments.</p><h3>Objective</h3><p>In this study, we revealed that the As-built and heat-treated mechanical properties differ from those achieved through traditional manufacturing methods, even when using the same alloy and heat treatments. This phenomenon arises from the intricated microstructures and porosity caused by the repetitive, rapid heating/cooling process involved.</p><h3>Results</h3><p>To quantitatively investigate the properties, the conventional heat treatments combining a hot isostatic pressing (HIP), solution, and aging treatment, were conducted on 17-4 PH stainless steel printed in both horizontal and vertical directions. Our findings demonstrate that HIP, coupled with aging treatment, was the most effective method for reducing porosity, and enhancing hardness and yield strength by <span>(56%)</span> and <span>(118%)</span>, respectively, while there was a slight decrease in elongation by <span>(5.6%)</span>. The high temperature and pressure during HIP enabled the recrystallization of As-built microstructure into lath martensite, and the aging treatment facilitated the production of precipitates to enhance the strength. The solution treatment, however, resulted in poor elongation to <span>(9.3%)</span> while the yield and tensile strength showed similar levels to As-built parts due to insufficient time to recrystallize the As-built microstructure.</p><h3>Conclusions</h3><p>We believe these results will offer valuable insights into the manufacturing and post processing not only of PBF 17-4PH stainless steel but also of other alloys.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1333 - 1342"},"PeriodicalIF":2.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141575132","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 : 2024-07-09DOI: 10.1007/s11340-024-01086-6
S. Zhan, A.J. Wagoner Johnson, S.B. Hutchens
Background
Though proposed by Lake and Yeoh in 1978 for vulcanized rubber characterization and possessing unique advantages with respect to traditional fracture characterization approaches, the Y-shaped cutting technique has been applied to a limited number of materials.
Objective
This limited implementation may be due to researchers’ unfamiliarity with the effects of Y-shaped cutting conditions and technique limitations, as well as a lack of standards. This review and best practices guide aims to provide a detailed road-map of the capabilities of Y-shaped cutting, with guidance for designing, executing, and interpreting its results.
Method
By performing Y-shaped cutting at a constant blade propagation rate, fracture initiation effects encountered in many ‘tearing’ tests are bypassed. Meanwhile, unlike other contact-driven fracture conditions (needle insertion or cutting), the ‘leg’ separation renders the cutting nearly ‘frictionless’ under a variety of conditions.
Results
Y-shaped cutting possesses two unique attributes. Under certain conditions (Zhang and Hutchens in Soft Matter 17(28):6728–6741, 2021), it can yield a fracture energy independent of sample and cutting implement geometry. In contrast to soft solid crack blunting, cutting reduces both the finite stretch and failure process zones to within a field of view readily imaged on a microscope, useful for microstructural studeis. To facilitate access to the above advantages, we summarize experimental variables and their role the fracture response and/or successful cutting and establish a pseudo-standard using silicone.
Conclusion
This overview and recommendations empowers researchers to implement this highly-tunable cutting method in order to provide insights into other classes of materials in the future.
背景虽然 Y 形切割技术由 Lake 和 Yeoh 于 1978 年提出,用于硫化橡胶的表征,与传统的断裂表征方法相比具有独特的优势,但应用于材料的数量有限。本综述和最佳实践指南旨在为 Y 形切割的功能提供详细的路线图,并为设计、执行和解释其结果提供指导。方法通过以恒定的刀片传播速度进行 Y 形切割,可以绕过许多 "撕裂 "试验中遇到的断裂起始效应。同时,与其他接触驱动的断裂条件(插针或切割)不同,"腿 "的分离使切割在各种条件下几乎 "无摩擦"。在特定条件下(Zhang 和 Hutchens,发表于《软物质》17(28):6728-6741, 2021 年),Y 型切割可产生与样品和切割工具几何形状无关的断裂能量。与软固体裂纹钝化不同的是,切割可将有限拉伸区和破坏过程区缩小到显微镜易于成像的视野范围内,有助于微观结构研究。为了便于利用上述优势,我们总结了实验变量及其对断裂响应和/或成功切割的作用,并使用硅酮建立了一个伪标准。
{"title":"Y-Shaped Cutting of Soft Solids: History and Best Practices","authors":"S. Zhan, A.J. Wagoner Johnson, S.B. Hutchens","doi":"10.1007/s11340-024-01086-6","DOIUrl":"10.1007/s11340-024-01086-6","url":null,"abstract":"<div><h3>Background</h3><p>Though proposed by Lake and Yeoh in 1978 for vulcanized rubber characterization and possessing unique advantages with respect to traditional fracture characterization approaches, the Y-shaped cutting technique has been applied to a limited number of materials.</p><h3>Objective</h3><p>This limited implementation may be due to researchers’ unfamiliarity with the effects of Y-shaped cutting conditions and technique limitations, as well as a lack of standards. This review and best practices guide aims to provide a detailed road-map of the capabilities of Y-shaped cutting, with guidance for designing, executing, and interpreting its results.</p><h3>Method</h3><p>By performing Y-shaped cutting at a constant blade propagation rate, fracture initiation effects encountered in many ‘tearing’ tests are bypassed. Meanwhile, unlike other contact-driven fracture conditions (needle insertion or cutting), the ‘leg’ separation renders the cutting nearly ‘frictionless’ under a variety of conditions.</p><h3>Results</h3><p>Y-shaped cutting possesses two unique attributes. Under certain conditions (Zhang and Hutchens in Soft Matter 17(28):6728–6741, 2021), it can yield a fracture energy independent of sample and cutting implement geometry. In contrast to soft solid crack blunting, cutting reduces <i>both</i> the finite stretch and failure process zones to within a field of view readily imaged on a microscope, useful for microstructural studeis. To facilitate access to the above advantages, we summarize experimental variables and their role the fracture response and/or successful cutting and establish a pseudo-standard using silicone.</p><h3>Conclusion</h3><p>This overview and recommendations empowers researchers to implement this highly-tunable cutting method in order to provide insights into other classes of materials in the future.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1185 - 1198"},"PeriodicalIF":2.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141575113","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 : 2024-07-03DOI: 10.1007/s11340-024-01096-4
B. Qiu, W. Li, C. Feng, X. Qu, H. Liu, X. Li
Background
Composite materials have been extensively used in various industry fields due to their distinguishing characteristics. However, low-velocity impact loads would undermine the mechanical properties of composite structures significantly.
Objective
To improve the integrity and safety of composite structures, it is imperative to unearth the accurate locations of low-velocity impact loads efficiently.
Methods
In this research, a novel approach hybridising response similarity search and optimisation strategy is developed. The innovation of the approach comes from the adoption of a “divide-and-conquer” strategy to alleviate extensive computations for time history reconstruction during the impact load localisation process so as to optimise computational efficiency and accuracy. In more detail, the approach is comprised of two localisation processes: (i) a coarse process to quickly identify several potential positions for an impact load via response similarity measurements based on time-domain and frequency-domain signals; (ii) a precise process to fine-tune the exact location of the impact load by minimising the nominal residual between the reconstructed and actual responses from the above potential positions.
Results
Experiments are conducted on a carbon fibre composite sandwich panel to validate and demonstrate the effectiveness and superiority of the approach in terms of localisation efficiency and accuracy. It indicates that the approach achieves 100% accuracy in impact load localisation. It also shows that the approach only takes approximately 4.0 s to localise 20 impact load cases, which is only about one-eighth of the time taken by the traditional optimisation strategy approach to fulfil the same function.
Conclusions
The hybrid approach designed based on response similarity search and optimisation strategy can greatly improve localisation efficiency and localisation accuracy.
{"title":"Efficient Localisation of Impact Load for Composite Structure Based on Response Similarity Search and Optimisation","authors":"B. Qiu, W. Li, C. Feng, X. Qu, H. Liu, X. Li","doi":"10.1007/s11340-024-01096-4","DOIUrl":"10.1007/s11340-024-01096-4","url":null,"abstract":"<div><h3>Background</h3><p>Composite materials have been extensively used in various industry fields due to their distinguishing characteristics. However, low-velocity impact loads would undermine the mechanical properties of composite structures significantly.</p><h3>Objective</h3><p>To improve the integrity and safety of composite structures, it is imperative to unearth the accurate locations of low-velocity impact loads efficiently.</p><h3>Methods</h3><p>In this research, a novel approach hybridising response similarity search and optimisation strategy is developed. The innovation of the approach comes from the adoption of a “divide-and-conquer” strategy to alleviate extensive computations for time history reconstruction during the impact load localisation process so as to optimise computational efficiency and accuracy. In more detail, the approach is comprised of two localisation processes: (i) a coarse process to quickly identify several potential positions for an impact load via response similarity measurements based on time-domain and frequency-domain signals; (ii) a precise process to fine-tune the exact location of the impact load by minimising the nominal residual between the reconstructed and actual responses from the above potential positions.</p><h3>Results</h3><p>Experiments are conducted on a carbon fibre composite sandwich panel to validate and demonstrate the effectiveness and superiority of the approach in terms of localisation efficiency and accuracy. It indicates that the approach achieves 100% accuracy in impact load localisation. It also shows that the approach only takes approximately 4.0 s to localise 20 impact load cases, which is only about one-eighth of the time taken by the traditional optimisation strategy approach to fulfil the same function.</p><h3>Conclusions</h3><p>The hybrid approach designed based on response similarity search and optimisation strategy can greatly improve localisation efficiency and localisation accuracy.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1311 - 1331"},"PeriodicalIF":2.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141549514","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 : 2024-07-02DOI: 10.1007/s11340-024-01094-6
G. Niu, R. Zhu, Y. Li, Z. Qu, H. Lei, P. Wang, H. Yang
Background
Digital image correlation (DIC) is widely used as a noncontact optical deformation measurement method. However, optical DIC encounters difficulties when measuring displacement and strain at high temperatures, including false deformation caused by heat haze and image overexposure caused by intense thermal radiation. X-ray imaging is not affected by these factors, so the combination of X-ray imaging and the DIC algorithm (X-DIC) holds the potential for measuring deformation during high-temperature tests.
Objective
This study investigated the ability of X-DIC to measure deformation in high-temperature experiments, expand the applicable temperature range of X-DIC, and provide a reliable method for obtaining deformation measurements in high-temperature experiments.
Methods
A combination of X-ray digital radiography (DR) images and the DIC algorithm was used to measure deformation. Numerical experiments based on synthetic images were used to evaluate the measurement accuracy of X-DIC, and the influence of different DIC parameters on the measurement error was discussed. Ductile iron and C/SiC composites were subjected to tensile tests at different temperatures from ambient temperature to 1000 °C, and different deformation measurement methods were used to simultaneously measure the deformation of the samples to verify the accuracy of the X-DIC results.
Results
In the numerical experiments, the displacement measurement error of X-DIC is less than 0.02 px. The relative error between the X-DIC and blue-light DIC measurements of the tensile deformation of ductile iron at 500 °C is 0.65%. When the deformation of the C/SiC composite materials was measured at 1000 °C, the root mean square error (RMSE) of the strain data obtained by X-DIC and optical DIC was 1.12 × 10–4.
Conclusions
These results prove that X-DIC has high measurement accuracy. Compared with optical DIC, X-DIC is insensitive to high-temperature environments and provides alternative experimental methods for high-temperature deformation measurements.
{"title":"X-Ray Digital Image Correlation: A Reliable Method for Deformation Measurement at 1000 °C","authors":"G. Niu, R. Zhu, Y. Li, Z. Qu, H. Lei, P. Wang, H. Yang","doi":"10.1007/s11340-024-01094-6","DOIUrl":"10.1007/s11340-024-01094-6","url":null,"abstract":"<div><h3>Background</h3><p>Digital image correlation (DIC) is widely used as a noncontact optical deformation measurement method. However, optical DIC encounters difficulties when measuring displacement and strain at high temperatures, including false deformation caused by heat haze and image overexposure caused by intense thermal radiation. X-ray imaging is not affected by these factors, so the combination of X-ray imaging and the DIC algorithm (X-DIC) holds the potential for measuring deformation during high-temperature tests.</p><h3>Objective</h3><p>This study investigated the ability of X-DIC to measure deformation in high-temperature experiments, expand the applicable temperature range of X-DIC, and provide a reliable method for obtaining deformation measurements in high-temperature experiments.</p><h3>Methods</h3><p>A combination of X-ray digital radiography (DR) images and the DIC algorithm was used to measure deformation. Numerical experiments based on synthetic images were used to evaluate the measurement accuracy of X-DIC, and the influence of different DIC parameters on the measurement error was discussed. Ductile iron and C/SiC composites were subjected to tensile tests at different temperatures from ambient temperature to 1000 °C, and different deformation measurement methods were used to simultaneously measure the deformation of the samples to verify the accuracy of the X-DIC results.</p><h3>Results</h3><p>In the numerical experiments, the displacement measurement error of X-DIC is less than 0.02 px. The relative error between the X-DIC and blue-light DIC measurements of the tensile deformation of ductile iron at 500 °C is 0.65%. When the deformation of the C/SiC composite materials was measured at 1000 °C, the root mean square error (RMSE) of the strain data obtained by X-DIC and optical DIC was 1.12 × 10<sup>–4</sup>.</p><h3>Conclusions</h3><p>These results prove that X-DIC has high measurement accuracy. Compared with optical DIC, X-DIC is insensitive to high-temperature environments and provides alternative experimental methods for high-temperature deformation measurements.</p></div>","PeriodicalId":552,"journal":{"name":"Experimental Mechanics","volume":"64 8","pages":"1263 - 1276"},"PeriodicalIF":2.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141521440","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 : 2024-07-02DOI: 10.1007/s11340-024-01084-8
L. Müller-Lohse, S. Hartmann, A. Richter, C. Rembe
Background
The experimental detection of small and large strains requires special approaches of full-field measurement techniques and their evaluation on 3D curved surfaces of components.
Objectives
Since classical digital image correlation methods have difficulties with the application of paints in some applications, one aim is to use a method in which the surface roughness is used to apply the strain calculation.
Methods
In this paper, 2D digital image correlation is applied to 2D intensity maps extracted from a coherence scanning interferometer together with height information. Height information are used to reconstruct the 3D motion of tracked material points. Surface interpolation and strain calculation are performed using globally formulated radial basis functions.
Results
The entire procedure leads to an appropriate technique for determining the in-plane strains in curved surfaces of parts, whereas the expected accuracy for various levels of the radial basis functions are discussed in detail.
Conclusions
Particularly, coherence scanning interferometry yields highly accurate height information. To smooth the surface motion, it turns out that in particular a regression analysis is required, where we apply radial basis functions with various approximation levels. This is an alternative procedure for surface strain determination.
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Pub Date : 2024-07-02DOI: 10.1007/s11340-024-01092-8
R.R. Kamath, J. Thomas, A.C. Chuang, B. Barua, J.-S. Park, L. Xiong, T.R. Watkins, S.S. Babu, G. Cola, D. Singh
Background
Understanding biaxial loading response at the microstructural level is crucial in helping better design sheet manufacturing processes and calibrate/validate material deformation models.
Objective
The objective of this work was to develop a low-cost testing apparatus to probe, with sufficient spatial resolution, the micro-mechanical response of a sheet material in-situ under biaxial loading conditions.
Methods
The testing apparatus fabricated as a part of this study operates in a similar fashion to a standard bulge test and uses oil pressure to generate biaxial loading conditions. This biaxial testing apparatus was operated within a synchrotron beamline to characterize the mechanical response of a flash-processed steel sheet using in-situ high-energy X-ray diffraction (XRD) measurements. The GSAS-II package was utilized to develop a workflow for the analysis of the large volume of diffraction data acquired. The workflow was then used to extract the peak position, width, and integrated intensity of the XRD peaks corresponding to the major body-centered cubic phase.
Results
The equi-biaxial nature of the loading in the measured area was independently corroborated using experimental (XRD) and simulation (finite element analysis) methods. Furthermore, we discuss the evolution of elastic strain in the major body-centered cubic phase as a function of applied oil pressure and location on the steel sheet.
Conclusions
A key advantage of the biaxial apparatus fabricated in this synchrotron study is demonstrated using the results obtained for the flash-processed steel sheet – i.e., mapping the lattice plane-dependent response to biaxial loading for a relatively large sample area in a spatially resolved manner.
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Pub Date : 2024-06-27DOI: 10.1007/s11340-024-01090-w
S. Vaidyanathan, G. S. Schajer
Background
Residual stresses exist in many manufactured materials and must be measured and taken into account for safe structural design. Established residual stress measurement methods are either destructive or require substantial material-dependent calibration.
Objective
The present work is aimed at developing an indentation-based method for measuring residual stress that causes minimal specimen damage, does not require a stress-free reference specimen, and has the capability to identify both the size and direction of the surface residual stresses. In this initial study, the simpler case of equi-biaxial stresses is addressed in preparation for subsequent general stress evaluations.
Methods
The surface displacements around an indentation made by a conical indenter are measured using digital image correlation. The residual stresses are then identified by comparison to the results of a finite model of the indentation process.
Results
The proposed method is shown to 2–5 times more sensitive to the presence of residual stresses than other commonly used indentation methods, particularly for materials with low Hollomon exponent n. In example measurements, axi-symmetric residual stresses were determined within 8% of the material yield stress.
Conclusions
The initial study presented here successfully considered the equal-biaxial stress case. The proposed method is attractive for future development because it gives directional information and therefore can be extended to the general non-equal-biaxial case.
背景许多人造材料中都存在残余应力,必须对其进行测量并将其纳入安全结构设计的考虑范围。本研究旨在开发一种基于压痕的残余应力测量方法,该方法对试样的破坏极小,不需要无应力参考试样,并且能够识别表面残余应力的大小和方向。在这项初步研究中,我们将处理较简单的等轴向应力情况,为后续的一般应力评估做准备。方法使用数字图像相关技术测量锥形压头压痕周围的表面位移。结果表明,与其他常用的压痕方法相比,所提出的方法对残余应力的敏感性提高了 2-5 倍,特别是对于霍洛蒙指数 n 较低的材料。在实例测量中,确定的轴对称残余应力在材料屈服应力的 8% 以内。所提出的方法提供了方向信息,因此可以扩展到一般的非等轴情况,因此对未来的发展很有吸引力。
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