F. Mentré, Sharon J. Swan, Elise S. Laffman-Johnson
No abstract is available for this article.
这篇文章没有摘要。
{"title":"Issue Information","authors":"F. Mentré, Sharon J. Swan, Elise S. Laffman-Johnson","doi":"10.1002/wcs.1326","DOIUrl":"https://doi.org/10.1002/wcs.1326","url":null,"abstract":"No abstract is available for this article.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/wcs.1326","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43344267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In friction stir welding (FSW), the inhomogeneous microstructure significantly affects the mechanical performance of the joints. The present study investigates the influence of microstructural asymmetry along the thickness on strain localization during tensile test using the digital image correlation technique and fracture morphology for double‐sided FSW (DS‐FSW) AA6061‐AA7075 joints. In top and bottom slices of the transverse tensile sample, nonhomogenous strain localization is noted in heat affected zone (HAZ) of the advancing side (AS), that is, AA6061‐T6, and also presents higher tensile strength. However, in the middle slice of the transverse sample, larger region including thermo‐mechanically affected zone and HAZ undergoes strain localization and exhibits higher elongation at failure. In longitudinal specimens, the strain distribution is homogeneous up to uniform elongation followed by strain concentration at a localised region and fracture. Electron backscatter diffraction revealed that the extent of dynamic recrystallization on the retreating side (AA7075‐T61) is higher than that observed on the AS of the weld. The grain orientation spread map showed a high fraction of recrystallized grains at the weld centre. Presence of major shear textures components B/B¯ and C both below the tool shoulder and weld centre regions are observed from pole figures. The recrystallized texture components P ({011}<112>), Goss ({110}<001>), Rotated Goss ({110}<110>), Cube ({001}<100>) and shear texture ({001}<110>) components is also noted at the weld centre. Middle slice both for longitudinal and transverse sample showed the finest dimple size on the fracture surfaces. The strain localization behaviour and tensile performance assessed for transverse and longitudinal samples can be helpful to find the load orientation dependency and safe design of DS‐FSW joints.
{"title":"Effect of microstructural variation on strain localization in double‐sided friction stir welded AA6061‐AA7075 joints","authors":"A. Garg, A. Bhattacharya","doi":"10.1111/str.12413","DOIUrl":"https://doi.org/10.1111/str.12413","url":null,"abstract":"In friction stir welding (FSW), the inhomogeneous microstructure significantly affects the mechanical performance of the joints. The present study investigates the influence of microstructural asymmetry along the thickness on strain localization during tensile test using the digital image correlation technique and fracture morphology for double‐sided FSW (DS‐FSW) AA6061‐AA7075 joints. In top and bottom slices of the transverse tensile sample, nonhomogenous strain localization is noted in heat affected zone (HAZ) of the advancing side (AS), that is, AA6061‐T6, and also presents higher tensile strength. However, in the middle slice of the transverse sample, larger region including thermo‐mechanically affected zone and HAZ undergoes strain localization and exhibits higher elongation at failure. In longitudinal specimens, the strain distribution is homogeneous up to uniform elongation followed by strain concentration at a localised region and fracture. Electron backscatter diffraction revealed that the extent of dynamic recrystallization on the retreating side (AA7075‐T61) is higher than that observed on the AS of the weld. The grain orientation spread map showed a high fraction of recrystallized grains at the weld centre. Presence of major shear textures components B/B¯ and C both below the tool shoulder and weld centre regions are observed from pole figures. The recrystallized texture components P ({011}<112>), Goss ({110}<001>), Rotated Goss ({110}<110>), Cube ({001}<100>) and shear texture ({001}<110>) components is also noted at the weld centre. Middle slice both for longitudinal and transverse sample showed the finest dimple size on the fracture surfaces. The strain localization behaviour and tensile performance assessed for transverse and longitudinal samples can be helpful to find the load orientation dependency and safe design of DS‐FSW joints.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48182313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The calibration of solid constitutive models with full‐field experimental data is a long‐standing challenge, especially in materials that undergo large deformations. In this paper, we propose a physics‐informed deep‐learning framework for the discovery of hyperelastic constitutive model parameterizations given full‐field surface displacement data and global force‐displacement data. Contrary to the majority of recent literature in this field, we work with the weak form of the governing equations rather than the strong form to impose physical constraints upon the neural network predictions. The approach presented in this paper is computationally efficient, suitable for irregular geometric domains, and readily ingests displacement data without the need for interpolation onto a computational grid. A selection of canonical hyperelastic material models suitable for different material classes is considered including the Neo–Hookean, Gent, and Blatz–Ko constitutive models as exemplars for general non‐linear elastic behaviour, elastomer behaviour with finite strain lock‐up, and compressible foam behaviour, respectively. We demonstrate that physics informed machine learning is an enabling technology and may shift the paradigm of how full‐field experimental data are utilized to calibrate constitutive models under finite deformations.
{"title":"Calibrating constitutive models with full‐field data via physics informed neural networks","authors":"Craig M. Hamel, K. Long, S. Kramer","doi":"10.1111/str.12431","DOIUrl":"https://doi.org/10.1111/str.12431","url":null,"abstract":"The calibration of solid constitutive models with full‐field experimental data is a long‐standing challenge, especially in materials that undergo large deformations. In this paper, we propose a physics‐informed deep‐learning framework for the discovery of hyperelastic constitutive model parameterizations given full‐field surface displacement data and global force‐displacement data. Contrary to the majority of recent literature in this field, we work with the weak form of the governing equations rather than the strong form to impose physical constraints upon the neural network predictions. The approach presented in this paper is computationally efficient, suitable for irregular geometric domains, and readily ingests displacement data without the need for interpolation onto a computational grid. A selection of canonical hyperelastic material models suitable for different material classes is considered including the Neo–Hookean, Gent, and Blatz–Ko constitutive models as exemplars for general non‐linear elastic behaviour, elastomer behaviour with finite strain lock‐up, and compressible foam behaviour, respectively. We demonstrate that physics informed machine learning is an enabling technology and may shift the paradigm of how full‐field experimental data are utilized to calibrate constitutive models under finite deformations.","PeriodicalId":51176,"journal":{"name":"Strain","volume":"59 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42230046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Issue Information","authors":"","doi":"10.1111/str.12391","DOIUrl":"https://doi.org/10.1111/str.12391","url":null,"abstract":"No abstract is available for this article.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45585104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microtubules (MTs) are highly dynamic polymers essential for a wide range of cellular physiologies, such as acting as directional railways for intracellular transport and position, guiding chromosome segregation during cell division, and controlling cell polarity and morphogenesis. Evidence has established that maintaining microtubule (MT) stability in neurons is vital for fundamental cellular and developmental processes, such as neurodevelopment, degeneration, and regeneration. To fulfill these diverse functions, the nervous system employs an arsenal of microtubule-associated proteins (MAPs) to control MT organization and function. Subsequent studies have identified that the disruption of MT function in neurons is one of the most prevalent and important pathological features of traumatic nerve damage and neurodegenerative diseases and that this disruption manifests as a reduction in MT polymerization and concomitant deregulation of the MT cytoskeleton, as well as downregulation of microtubule-associated protein (MAP) expression. A variety of MT-targeting agents that reverse this pathological condition, which is regarded as a therapeutic opportunity to intervene the onset and development of these nervous system abnormalities, is currently under development. Here, we provide an overview of the MT-intrinsic organization process and how MAPs interact with the MT cytoskeleton to promote MT polymerization, stabilization, and bundling. We also highlight recent advances in MT-targeting therapeutic agents applied to various neurological disorders. Together, these findings increase our current understanding of the function and regulation of MT organization in nerve growth and regeneration.
{"title":"Microtubule Organization Is Essential for Maintaining Cellular Morphology and Function.","authors":"Lijiang Huang, Yan Peng, Xuetao Tao, Xiaoxiao Ding, Rui Li, Yongsheng Jiang, Wei Zuo","doi":"10.1155/2022/1623181","DOIUrl":"10.1155/2022/1623181","url":null,"abstract":"<p><p>Microtubules (MTs) are highly dynamic polymers essential for a wide range of cellular physiologies, such as acting as directional railways for intracellular transport and position, guiding chromosome segregation during cell division, and controlling cell polarity and morphogenesis. Evidence has established that maintaining microtubule (MT) stability in neurons is vital for fundamental cellular and developmental processes, such as neurodevelopment, degeneration, and regeneration. To fulfill these diverse functions, the nervous system employs an arsenal of microtubule-associated proteins (MAPs) to control MT organization and function. Subsequent studies have identified that the disruption of MT function in neurons is one of the most prevalent and important pathological features of traumatic nerve damage and neurodegenerative diseases and that this disruption manifests as a reduction in MT polymerization and concomitant deregulation of the MT cytoskeleton, as well as downregulation of microtubule-associated protein (MAP) expression. A variety of MT-targeting agents that reverse this pathological condition, which is regarded as a therapeutic opportunity to intervene the onset and development of these nervous system abnormalities, is currently under development. Here, we provide an overview of the MT-intrinsic organization process and how MAPs interact with the MT cytoskeleton to promote MT polymerization, stabilization, and bundling. We also highlight recent advances in MT-targeting therapeutic agents applied to various neurological disorders. Together, these findings increase our current understanding of the function and regulation of MT organization in nerve growth and regeneration.</p>","PeriodicalId":51176,"journal":{"name":"Strain","volume":"22 1","pages":"1623181"},"PeriodicalIF":0.0,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8920689/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85426175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Estimating stress in statically undetermined tests remains an issue in experimental mechanics. Most estimation methods rely on the a priori choice of a behaviour equation leading to an unavoidable model bias. Recently, efforts have been made to propose methods circumventing the parametric description of constitutive behaviours. In particular, Leygue et al. (2018) proposed a new paradigm called data‐driven identification (DDI). An extension of Leygue's method to history‐dependent materials is proposed in this paper. The formulation of the problem and its resolution are presented with emphasis on boundary conditions. The method is tested on real experimental data where the elasto‐plastic material is subjected to the formation of Piobert–Lüders bands. We finally show that the DDI allows to obtain balanced fields that are closer (more consistent) to the field measurements than the fields obtained by parametric identification strategies, even more in the presence of strain localization bands whose kinematics are usually not described by a standard constitutive model.
静力待定试验中的应力估计一直是实验力学中的一个问题。大多数估计方法依赖于行为方程的先验选择，导致不可避免的模型偏差。最近，人们提出了一些绕过本构行为参数描述的方法。特别是，Leygue等人(2018)提出了一种称为数据驱动识别(DDI)的新范式。本文将莱格的方法扩展到历史相关材料。给出了问题的表述和解决方法，重点讨论了边界条件。该方法在实际实验数据上进行了测试，其中弹塑性材料受到piobert - l ders带的形成。我们最后表明，与参数识别策略获得的场相比，DDI允许获得更接近(更一致)场测量的平衡场，甚至更多地存在其运动学通常不能由标准本构模型描述的应变局部化带。
{"title":"Non‐parametric stress field estimation for history‐dependent materials: Application to ductile material exhibiting Piobert–Lüders localization bands","authors":"Raphaël Langlois, M. Coret, J. Réthoré","doi":"10.1111/str.12410","DOIUrl":"https://doi.org/10.1111/str.12410","url":null,"abstract":"Estimating stress in statically undetermined tests remains an issue in experimental mechanics. Most estimation methods rely on the a priori choice of a behaviour equation leading to an unavoidable model bias. Recently, efforts have been made to propose methods circumventing the parametric description of constitutive behaviours. In particular, Leygue et al. (2018) proposed a new paradigm called data‐driven identification (DDI). An extension of Leygue's method to history‐dependent materials is proposed in this paper. The formulation of the problem and its resolution are presented with emphasis on boundary conditions. The method is tested on real experimental data where the elasto‐plastic material is subjected to the formation of Piobert–Lüders bands. We finally show that the DDI allows to obtain balanced fields that are closer (more consistent) to the field measurements than the fields obtained by parametric identification strategies, even more in the presence of strain localization bands whose kinematics are usually not described by a standard constitutive model.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47824454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Güden, Alican Tuncay Alpkaya, Burcu Arslan Hamat, Burak Hızlı, A. Taşdemirci, A. Tanrıkulu, H. Yavaş
The effect of the number of cells, strut diameter and face sheet on the compression of electron‐beam‐melt (EBM) Ti6Al4V (Ti64) body‐centred‐cubic (BCC) lattices was investigated experimentally and numerically. The lattices with the same relative density (~0.182) were fabricated with and without 2‐mm‐thick face sheets in 10 and 5 mm cell size, 8–125 unit cell (two to five cells/edge) and 2 and 1 mm strut diameter. The experimental compression tests were further numerically simulated in the LS‐DYNA. Experimentally two bending‐dominated crushing modes, namely, lateral and diagonal layer crushing, were determined. The numerical models however exhibited merely a bending‐dominated lateral layer crushing mode when the erosion strain was 0.4 and without face‐sheet models showed a diagonal layer crushing mode when the erosion strain was 0.3. Lower erosion strains promoted a diagonal layer crushing mode by introducing geometrical inhomogeneity to the lattice, leading to strain localisation as similar to the face sheets which introduced extensive strut bending in the layers adjacent to the face sheets. The face‐sheet model showed a higher but decreasing collapse strength at an increasing number of cells, just as opposite to the without face‐sheet model, and the collapse strength of both models converged when the number of cells was higher than five‐cell/edge. The decrease/increase of the collapse strengths of lattices before the critical number of cells was claimed mainly due to the size‐imposed lattice boundary condition, rather than the specimen volume. The difference in the experimental collapse strengths between the 5‐ and the 10‐mm cell‐size lattices was ascribed to the variations in the microstructures—hence the material model parameters between the small‐diameter and the large‐diameter EBM‐Ti64 strut lattices.
{"title":"The quasi‐static crush response of electron‐beam‐melt Ti6Al4V body‐centred‐cubic lattices: The effect of the number of cells, strut diameter and face sheet","authors":"M. Güden, Alican Tuncay Alpkaya, Burcu Arslan Hamat, Burak Hızlı, A. Taşdemirci, A. Tanrıkulu, H. Yavaş","doi":"10.1111/str.12411","DOIUrl":"https://doi.org/10.1111/str.12411","url":null,"abstract":"The effect of the number of cells, strut diameter and face sheet on the compression of electron‐beam‐melt (EBM) Ti6Al4V (Ti64) body‐centred‐cubic (BCC) lattices was investigated experimentally and numerically. The lattices with the same relative density (~0.182) were fabricated with and without 2‐mm‐thick face sheets in 10 and 5 mm cell size, 8–125 unit cell (two to five cells/edge) and 2 and 1 mm strut diameter. The experimental compression tests were further numerically simulated in the LS‐DYNA. Experimentally two bending‐dominated crushing modes, namely, lateral and diagonal layer crushing, were determined. The numerical models however exhibited merely a bending‐dominated lateral layer crushing mode when the erosion strain was 0.4 and without face‐sheet models showed a diagonal layer crushing mode when the erosion strain was 0.3. Lower erosion strains promoted a diagonal layer crushing mode by introducing geometrical inhomogeneity to the lattice, leading to strain localisation as similar to the face sheets which introduced extensive strut bending in the layers adjacent to the face sheets. The face‐sheet model showed a higher but decreasing collapse strength at an increasing number of cells, just as opposite to the without face‐sheet model, and the collapse strength of both models converged when the number of cells was higher than five‐cell/edge. The decrease/increase of the collapse strengths of lattices before the critical number of cells was claimed mainly due to the size‐imposed lattice boundary condition, rather than the specimen volume. The difference in the experimental collapse strengths between the 5‐ and the 10‐mm cell‐size lattices was ascribed to the variations in the microstructures—hence the material model parameters between the small‐diameter and the large‐diameter EBM‐Ti64 strut lattices.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48059492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We compute three‐dimensional displacement vector fields to estimate the deformation of microstructural data sets in mechanical tests. For this, we extend the well‐known optical flow by Brox et al. to three dimensions, with special focus on the discretization of nonlinear terms. We evaluate our method first by synthetically deforming foams and comparing against this ground truth and second with data sets of samples that underwent real mechanical tests. Our results are compared to those from state‐of‐the‐art algorithms in materials science and medical image registration. By a thorough evaluation, we show that our proposed method is able to resolve the displacement best among all chosen comparison methods.
{"title":"3D optical flow for large CT data of materials microstructures","authors":"Tessa Nogatz, C. Redenbach, K. Schladitz","doi":"10.1111/str.12412","DOIUrl":"https://doi.org/10.1111/str.12412","url":null,"abstract":"We compute three‐dimensional displacement vector fields to estimate the deformation of microstructural data sets in mechanical tests. For this, we extend the well‐known optical flow by Brox et al. to three dimensions, with special focus on the discretization of nonlinear terms. We evaluate our method first by synthetically deforming foams and comparing against this ground truth and second with data sets of samples that underwent real mechanical tests. Our results are compared to those from state‐of‐the‐art algorithms in materials science and medical image registration. By a thorough evaluation, we show that our proposed method is able to resolve the displacement best among all chosen comparison methods.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44951387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present paper describes a novel experimental method for characterising the confined shear strength of concrete or rock‐like materials based on the use of pre‐stressed sample. This method, called PS‐PTS (Pre‐Stressed Punch‐Through‐Shear), employs a metallic confinement cell that is first quasi‐statically deformed so the concrete sample can be introduced in between the cell jaws. The confinement force is transmitted to the sample in the unloading stage. It is shown that this initial pre‐load level can be predicted by an elastic closed‐form solution. Strain‐gauges glued on the cell allow the confinement level applied to the sample to be experimentally measured during the pre‐stressing stage and the shear stage. In the next stage, the central part of the sample is subjected to a differential displacement towards the lateral parts by means of a hydraulic press so the confined shear strength of the tested material can be deduced. The results are compared to the data previously obtained with an “oedometric” confinement cell in terms of confinement stresses and shear strength.
本文描述了一种新的基于预应力试样的混凝土或岩石类材料的限剪强度表征实验方法。这种方法被称为PS‐PTS (Pre - Stressed Punch - Through - Shear)，采用金属约束单元，首先进行准静态变形，因此混凝土样品可以在单元颚之间引入。在卸载阶段，约束力传递给试样。结果表明，这种初始预载荷水平可以用弹性闭合解来预测。粘在电池上的应变片允许在预应力阶段和剪切阶段实验测量施加到样品上的约束水平。在下一阶段，通过液压机对样品的中心部分施加向侧向部分的微分位移，从而可以推断出被测材料的约束抗剪强度。在约束应力和剪切强度方面，将结果与先前使用“尺寸测量”约束单元获得的数据进行了比较。
{"title":"A novel experimental method to characterise the shear strength of concrete based on pre‐stressed samples","authors":"P. Forquin, R. Abdul‐Rahman, D. Saletti","doi":"10.1111/str.12407","DOIUrl":"https://doi.org/10.1111/str.12407","url":null,"abstract":"The present paper describes a novel experimental method for characterising the confined shear strength of concrete or rock‐like materials based on the use of pre‐stressed sample. This method, called PS‐PTS (Pre‐Stressed Punch‐Through‐Shear), employs a metallic confinement cell that is first quasi‐statically deformed so the concrete sample can be introduced in between the cell jaws. The confinement force is transmitted to the sample in the unloading stage. It is shown that this initial pre‐load level can be predicted by an elastic closed‐form solution. Strain‐gauges glued on the cell allow the confinement level applied to the sample to be experimentally measured during the pre‐stressing stage and the shear stage. In the next stage, the central part of the sample is subjected to a differential displacement towards the lateral parts by means of a hydraulic press so the confined shear strength of the tested material can be deduced. The results are compared to the data previously obtained with an “oedometric” confinement cell in terms of confinement stresses and shear strength.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41727590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mechanical behaviour of the nickel‐based superalloy In718, as processed from laser powder bed fusion (L‐PBF) additive manufacturing, is characterized at high temperature, from 800 to 1100°C. Samples built by L‐PBF are submitted to sequences combining uniaxial tensile load at different prescribed velocities, and relaxation steps of different durations, operated under resistive heating under vacuum, with a home‐developed testing machine. Tests are equipped with force evolution measurement, with infra‐red field imaging and thermocouples to capture the non‐uniform temperature distributions induced by resistive heating, and with digital image correlation to capture the non‐linear displacement fields. An inverse finite element strategy is developed to identify the parameters of a temperature‐dependent elastic‐viscoplastic behaviour model. The strategy is based on (i) direct finite element simulations of tests, (ii) a cost function expressing the distance between calculated and measured quantities, and (iii) a minimization algorithm. Direct numerical simulations are performed on a limited part of the working zone of samples, the zone of interest, with applied boundary conditions provided by DIC records and with an imposed temperature distribution provided by infra‐red imaging. The cost function is based on the force evolution only, for a series of different tests operated at different nominal temperatures. Optimum values of constitutive parameters are obtained by minimizing the cost function value, which is achieved with the home‐developed optimization platform MOOPI. Finally, the identified parameters are discussed with respect to the literature.
{"title":"A new localized inverse identification method for high temperature testing under resistive heating: Application to the elastic‐viscoplastic behaviour of L‐PBF processed In718","authors":"Feng Gao, B. Macquaire, Yancheng Zhang, M. Bellet","doi":"10.1111/str.12409","DOIUrl":"https://doi.org/10.1111/str.12409","url":null,"abstract":"The mechanical behaviour of the nickel‐based superalloy In718, as processed from laser powder bed fusion (L‐PBF) additive manufacturing, is characterized at high temperature, from 800 to 1100°C. Samples built by L‐PBF are submitted to sequences combining uniaxial tensile load at different prescribed velocities, and relaxation steps of different durations, operated under resistive heating under vacuum, with a home‐developed testing machine. Tests are equipped with force evolution measurement, with infra‐red field imaging and thermocouples to capture the non‐uniform temperature distributions induced by resistive heating, and with digital image correlation to capture the non‐linear displacement fields. An inverse finite element strategy is developed to identify the parameters of a temperature‐dependent elastic‐viscoplastic behaviour model. The strategy is based on (i) direct finite element simulations of tests, (ii) a cost function expressing the distance between calculated and measured quantities, and (iii) a minimization algorithm. Direct numerical simulations are performed on a limited part of the working zone of samples, the zone of interest, with applied boundary conditions provided by DIC records and with an imposed temperature distribution provided by infra‐red imaging. The cost function is based on the force evolution only, for a series of different tests operated at different nominal temperatures. Optimum values of constitutive parameters are obtained by minimizing the cost function value, which is achieved with the home‐developed optimization platform MOOPI. Finally, the identified parameters are discussed with respect to the literature.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44161937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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