A vibration data‐based machine learning architecture is designed for structural health monitoring (SHM) of a steel plane frame structure. This architecture uses a Bag‐of‐Features algorithm that extracts the speeded‐up robust features (SURF) from the time‐frequency scalogram images of the registered vibration data. The discriminative image features are then quantised to a visual vocabulary using K‐means clustering. Finally, a support vector machine (SVM) is trained to distinguish the undamaged and multiple damage cases of the frame structure based on the discriminative features. The potential of the machine learning architecture is tested for an unseen dataset that was not used in training as well as with some datasets from entirely new damages close to existing (i.e., trained) damage classes. The results are then compared with those obtained using three other combinations of features and learning algorithms—(i) histogram of oriented gradients (HOG) feature with SVM, (ii) SURF feature with k‐nearest neighbours (KNN) and (iii) HOG feature with KNN. In order to examine the robustness of the approach, the study is further extended by considering environmental variabilities along with the localisation and quantification of damage. The experimental results show that the machine learning architecture can effectively classify the undamaged and different joint damage classes with high testing accuracy that indicates its SHM potential for such frame structures.
{"title":"Vibration data‐driven machine learning architecture for structural health monitoring of steel frame structures","authors":"M. Naresh, S. Sikdar, J. Pal, S. Sikdar","doi":"10.1111/str.12439","DOIUrl":"https://doi.org/10.1111/str.12439","url":null,"abstract":"A vibration data‐based machine learning architecture is designed for structural health monitoring (SHM) of a steel plane frame structure. This architecture uses a Bag‐of‐Features algorithm that extracts the speeded‐up robust features (SURF) from the time‐frequency scalogram images of the registered vibration data. The discriminative image features are then quantised to a visual vocabulary using K‐means clustering. Finally, a support vector machine (SVM) is trained to distinguish the undamaged and multiple damage cases of the frame structure based on the discriminative features. The potential of the machine learning architecture is tested for an unseen dataset that was not used in training as well as with some datasets from entirely new damages close to existing (i.e., trained) damage classes. The results are then compared with those obtained using three other combinations of features and learning algorithms—(i) histogram of oriented gradients (HOG) feature with SVM, (ii) SURF feature with k‐nearest neighbours (KNN) and (iii) HOG feature with KNN. In order to examine the robustness of the approach, the study is further extended by considering environmental variabilities along with the localisation and quantification of damage. The experimental results show that the machine learning architecture can effectively classify the undamaged and different joint damage classes with high testing accuracy that indicates its SHM potential for such frame structures.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48882741","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}
L. Morichelli, G. Chiappini, A. Lattanzi, E. Santecchia, M. Rossi
The metal additive manufacturing (AM) is a technology that is rapidly spreading in the industrial sector with its enormous potential in making components with complex shapes and low weight, ensuring a high structural strength. However, the mechanical properties of the components depend on the printing process, and the interactions between the process variables and the final material behaviour is still not totally understood. In this work, 12 different types of tensile specimen were built by AM using the laser powder bed fusion (L‐PBF) technique; the used material is the 316L stainless steel. The specimens have the same geometry and the same process parameters in terms of layer thickness, hatch space, laser power, spot diameter, scanning speed and platform preheating temperature, while different laser scan strategies and building orientations are evaluated. The scope is to characterize the plastic behaviour of such specimens and study the differences due to distinct printing strategies. Stereo digital image correlation (stereo‐DIC) was used to evaluate the deformation state and analyse the material anisotropy. Finally, the microstructure and presence of defects were investigated through the optical microscopy (OM) and the scanning electron microscopy (SEM). The analysis shows how the plastic behaviour and the formation of defects are remarkably influenced by the laser scan strategy and by the building orientation.
{"title":"Combined effect of process variables on the plastic behaviour of 316L stainless steel printed by L‐PBF","authors":"L. Morichelli, G. Chiappini, A. Lattanzi, E. Santecchia, M. Rossi","doi":"10.1111/str.12438","DOIUrl":"https://doi.org/10.1111/str.12438","url":null,"abstract":"The metal additive manufacturing (AM) is a technology that is rapidly spreading in the industrial sector with its enormous potential in making components with complex shapes and low weight, ensuring a high structural strength. However, the mechanical properties of the components depend on the printing process, and the interactions between the process variables and the final material behaviour is still not totally understood. In this work, 12 different types of tensile specimen were built by AM using the laser powder bed fusion (L‐PBF) technique; the used material is the 316L stainless steel. The specimens have the same geometry and the same process parameters in terms of layer thickness, hatch space, laser power, spot diameter, scanning speed and platform preheating temperature, while different laser scan strategies and building orientations are evaluated. The scope is to characterize the plastic behaviour of such specimens and study the differences due to distinct printing strategies. Stereo digital image correlation (stereo‐DIC) was used to evaluate the deformation state and analyse the material anisotropy. Finally, the microstructure and presence of defects were investigated through the optical microscopy (OM) and the scanning electron microscopy (SEM). The analysis shows how the plastic behaviour and the formation of defects are remarkably influenced by the laser scan strategy and by the building orientation.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47536510","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}
Single‐reed musical instruments, such as the saxophone, generate sound through a complex interplay between the mechanics of the reed and the hydrodynamic and acoustic pressure in the instrument mouthpiece. To understand this complex mechanism, experimental data are lacking. This paper presents full‐field, time‐resolved measurements of strain and displacement of a vibrating saxophone reed, measured under mimicked realistic playing conditions. It is found that strain along the length axis of the reed is mainly expansive, except in a small zone near the tip where it becomes compressive when the reed touches the front edge of the mouthpiece. At the instant in the vibration phase where the reed touches the mouthpiece, significant bending and compressive strain appear along the direction perpendicular to the reed axis. Strain magnitudes in both directions are similar, with absolute values of 0.1%. Full‐field strain maps reveal subtle characteristics which are not revealed by displacement measurements. Bi‐axial bending and strain may be an essential component in reed mechanics, which up till now has been fully neglected in modelling.
{"title":"Time‐resolved strain and deformation measurement on the vibrating saxophone reed","authors":"Enis Ukshini, J. Dirckx","doi":"10.1111/str.12437","DOIUrl":"https://doi.org/10.1111/str.12437","url":null,"abstract":"Single‐reed musical instruments, such as the saxophone, generate sound through a complex interplay between the mechanics of the reed and the hydrodynamic and acoustic pressure in the instrument mouthpiece. To understand this complex mechanism, experimental data are lacking. This paper presents full‐field, time‐resolved measurements of strain and displacement of a vibrating saxophone reed, measured under mimicked realistic playing conditions. It is found that strain along the length axis of the reed is mainly expansive, except in a small zone near the tip where it becomes compressive when the reed touches the front edge of the mouthpiece. At the instant in the vibration phase where the reed touches the mouthpiece, significant bending and compressive strain appear along the direction perpendicular to the reed axis. Strain magnitudes in both directions are similar, with absolute values of 0.1%. Full‐field strain maps reveal subtle characteristics which are not revealed by displacement measurements. Bi‐axial bending and strain may be an essential component in reed mechanics, which up till now has been fully neglected in modelling.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44801676","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}
With the advent of camera‐based full‐field measurement techniques such as digital image correlation (DIC), researchers have been trying to exploit such rich data sets through the use of more complex test configurations than the standard ones (uniaxial tension/compression, bending etc.). This new paradigm in mechanical testing of materials has recently been christened ‘Material Testing 2.0’. This paper provides a brief overview of this field, which is currently seeing a large increase in research effort.
{"title":"Material Testing 2.0: A brief review","authors":"F. Pierron","doi":"10.1111/str.12434","DOIUrl":"https://doi.org/10.1111/str.12434","url":null,"abstract":"With the advent of camera‐based full‐field measurement techniques such as digital image correlation (DIC), researchers have been trying to exploit such rich data sets through the use of more complex test configurations than the standard ones (uniaxial tension/compression, bending etc.). This new paradigm in mechanical testing of materials has recently been christened ‘Material Testing 2.0’. This paper provides a brief overview of this field, which is currently seeing a large increase in research effort.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43002969","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}
Concrete shear strength is one of important parameters in structural design and analysis. Brittle failure of concrete under shear has substantial impact on performance of structure. Concrete shear strength as stipulated in standard codes of different nations is based on RC beam elements. Majority of research also focused on reinforced elements or on indirect shearing. There have been few studies performed on plain concrete subjected to pure shear. Hence, pure shear strength of plain concrete is not established. In light of foregoing, the present work attempts to build loading method that is efficient and capable of creating uniform shear force in standard specimen. The study investigates fracture behaviour of plain concrete when subjected to pure shear force. The pure shear state of specimen is verified using Mohr's circle method. FEA is performed to validate experimental data. The proposed test set‐up is effective in determining pure shear strength of plain concrete.
{"title":"Shear strength of plain concrete","authors":"R. Jajodia, S. Gadve","doi":"10.1111/str.12436","DOIUrl":"https://doi.org/10.1111/str.12436","url":null,"abstract":"Concrete shear strength is one of important parameters in structural design and analysis. Brittle failure of concrete under shear has substantial impact on performance of structure. Concrete shear strength as stipulated in standard codes of different nations is based on RC beam elements. Majority of research also focused on reinforced elements or on indirect shearing. There have been few studies performed on plain concrete subjected to pure shear. Hence, pure shear strength of plain concrete is not established. In light of foregoing, the present work attempts to build loading method that is efficient and capable of creating uniform shear force in standard specimen. The study investigates fracture behaviour of plain concrete when subjected to pure shear force. The pure shear state of specimen is verified using Mohr's circle method. FEA is performed to validate experimental data. The proposed test set‐up is effective in determining pure shear strength of plain concrete.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47603760","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}
Ruike Shi, S. Avril, Haitian Yang, V. A. Acosta Santamaría, Yue Mei, Yiqian He
Biphasic hyperelastic models have become popular for soft hydrated tissues, and there is a pressing need for appropriate identification methods using full‐field measurement techniques such as digital volume correlation. This paper proposes to address this need with the virtual fields method (VFM). The main asset of the proposed approach is that it avoids the repeated resolution of complex nonlinear finite element models. By choosing special virtual fields, the VFM approach can extract hyperelastic parameters of the solid part of the biphasic medium without resorting to identifying the model parameters driving the osmotic effects in the interstitial fluid. The proposed approach is verified and validated through three different examples: the first and second using simulated data and then the third using experimental data obtained from porcine descending thoracic aortas samples in osmotically active solution.
{"title":"Adaptation of the virtual fields method for the identification of biphasic hyperelastic model parameters in soft biological tissues with osmotic swelling","authors":"Ruike Shi, S. Avril, Haitian Yang, V. A. Acosta Santamaría, Yue Mei, Yiqian He","doi":"10.1111/str.12435","DOIUrl":"https://doi.org/10.1111/str.12435","url":null,"abstract":"Biphasic hyperelastic models have become popular for soft hydrated tissues, and there is a pressing need for appropriate identification methods using full‐field measurement techniques such as digital volume correlation. This paper proposes to address this need with the virtual fields method (VFM). The main asset of the proposed approach is that it avoids the repeated resolution of complex nonlinear finite element models. By choosing special virtual fields, the VFM approach can extract hyperelastic parameters of the solid part of the biphasic medium without resorting to identifying the model parameters driving the osmotic effects in the interstitial fluid. The proposed approach is verified and validated through three different examples: the first and second using simulated data and then the third using experimental data obtained from porcine descending thoracic aortas samples in osmotically active solution.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42418694","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}
P. Jaiswal, Raj Kumar, Thibault Juwet, G. Luyckx, Cedric Verhaeghe, W. De Waele
The strength and deformation of full‐scale adhesively bonded multi‐material joints is studied in this paper. Four joints with a thick layer of methyl methacrylate adhesive (MMA) have been manufactured in shipyard conditions. In two specimens, cracks have been introduced at steel–adhesive and composite–adhesive interfaces. One cracked and one un‐cracked specimen were subjected to quasi‐static tensile testing; the two remaining specimens were stepwise loaded/unloaded with increasing load until failure. The strain in the adhesive layers was measured with digital image correlation (DIC). This showed a predominant shear deformation and dissimilar shear strain patterns for different bond lines. Fibre Bragg (FBG) sensors were used to monitor strains at steel and composite constituents and to detect the onset and evolution of damage in the un‐cracked specimen. Strains measured by FBG sensors correspond well with DIC results at nearby regions. All specimens failed by delamination of the composite panel near the composite–adhesive interface.
{"title":"Experimental deformation analysis of an adhesively bonded multi‐material joint for marine applications","authors":"P. Jaiswal, Raj Kumar, Thibault Juwet, G. Luyckx, Cedric Verhaeghe, W. De Waele","doi":"10.1111/str.12433","DOIUrl":"https://doi.org/10.1111/str.12433","url":null,"abstract":"The strength and deformation of full‐scale adhesively bonded multi‐material joints is studied in this paper. Four joints with a thick layer of methyl methacrylate adhesive (MMA) have been manufactured in shipyard conditions. In two specimens, cracks have been introduced at steel–adhesive and composite–adhesive interfaces. One cracked and one un‐cracked specimen were subjected to quasi‐static tensile testing; the two remaining specimens were stepwise loaded/unloaded with increasing load until failure. The strain in the adhesive layers was measured with digital image correlation (DIC). This showed a predominant shear deformation and dissimilar shear strain patterns for different bond lines. Fibre Bragg (FBG) sensors were used to monitor strains at steel and composite constituents and to detect the onset and evolution of damage in the un‐cracked specimen. Strains measured by FBG sensors correspond well with DIC results at nearby regions. All specimens failed by delamination of the composite panel near the composite–adhesive interface.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47259245","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}
J. Considine, Nathan J. Bechle, F. Pierron, David E. Krestschmann
Knowledge of local mechanical behaviour of wood is especially important as silvicultural practices are modified to allow wood to compete as a relevant material in high technology applications. Challenges associated with identification of local mechanical behaviour have resulted in simplified test geometries designed to determine one or two constitutive parameters. The objective of this work was to design and simulate an entire experiment developed to simultaneously identify the earlywood and latewood orthotropic stiffnesses in loblolly pine in a single specimen and load geometry. The virtual experiment was capable of evaluating optimal orthotropy orientation for reduced identification errors and indicating most favourable choices for data smoothing filters and identification methodology. Additionally, certain ring spacing and latewood percentages were shown to produce large errors, but those combinations are unlikely to occur naturally. The simulation was able to identify Q11,Q22 , and Q66 with approximately ±10% error; the Q12 error was larger with more scatter. The methodology presented here contributes to the best practices available for heterogeneous stiffness identification.
{"title":"Optimized identification of earlywood and latewood stiffnesses in loblolly pine in simulated experiments","authors":"J. Considine, Nathan J. Bechle, F. Pierron, David E. Krestschmann","doi":"10.1111/str.12432","DOIUrl":"https://doi.org/10.1111/str.12432","url":null,"abstract":"Knowledge of local mechanical behaviour of wood is especially important as silvicultural practices are modified to allow wood to compete as a relevant material in high technology applications. Challenges associated with identification of local mechanical behaviour have resulted in simplified test geometries designed to determine one or two constitutive parameters. The objective of this work was to design and simulate an entire experiment developed to simultaneously identify the earlywood and latewood orthotropic stiffnesses in loblolly pine in a single specimen and load geometry. The virtual experiment was capable of evaluating optimal orthotropy orientation for reduced identification errors and indicating most favourable choices for data smoothing filters and identification methodology. Additionally, certain ring spacing and latewood percentages were shown to produce large errors, but those combinations are unlikely to occur naturally. The simulation was able to identify Q11,Q22 , and Q66 with approximately ±10% error; the Q12 error was larger with more scatter. The methodology presented here contributes to the best practices available for heterogeneous stiffness identification.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47385938","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}
Diego L. Brítez, M. Prime, Sana Werda, R. Laheurte, P. Darnis, O. Cahuc
Many destructive methods for measuring residual stresses such as the slitting method require an inverse analysis to solve the problem. The accuracy of the result as well as an uncertainty component (the model uncertainty) depends on the basis functions used in the inverse solution. The use of a series expansion as the basis functions for the inverse solution was analysed in a previous work for the particular case where functions orders grew consecutively. The present work presents a new estimation of the model uncertainty and a new improved methodology to select the final basis functions for the case where the basis is composed of polynomials. Including nonconsecutive polynomial orders in the basis generates a larger space of possible solutions to be evaluated and allows the possibility to include higher‐order polynomials. The paper includes a comparison with two other inverse analyses methodologies applied to synthetically generated data. With the new methodology, the final error is reduced and the uncertainty estimation improved.
{"title":"Uncertainty reduction in residual stress measurements by an optimised inverse solution using nonconsecutive polynomials","authors":"Diego L. Brítez, M. Prime, Sana Werda, R. Laheurte, P. Darnis, O. Cahuc","doi":"10.1111/str.12430","DOIUrl":"https://doi.org/10.1111/str.12430","url":null,"abstract":"Many destructive methods for measuring residual stresses such as the slitting method require an inverse analysis to solve the problem. The accuracy of the result as well as an uncertainty component (the model uncertainty) depends on the basis functions used in the inverse solution. The use of a series expansion as the basis functions for the inverse solution was analysed in a previous work for the particular case where functions orders grew consecutively. The present work presents a new estimation of the model uncertainty and a new improved methodology to select the final basis functions for the case where the basis is composed of polynomials. Including nonconsecutive polynomial orders in the basis generates a larger space of possible solutions to be evaluated and allows the possibility to include higher‐order polynomials. The paper includes a comparison with two other inverse analyses methodologies applied to synthetically generated data. With the new methodology, the final error is reduced and the uncertainty estimation improved.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45480668","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}
Thermomechanical parameters are important indicators for evaluating the mechanical properties of superalloys and generally include the coefficients of stiffness and thermal expansion at high temperatures. At present, there are few methods for simultaneously characterising the thermomechanical parameters of superalloys, especially single‐crystal superalloys. To satisfy the demand for simultaneously identifying the thermomechanical parameters of orthotropic superalloys, an optimised virtual fields method for decoupling the thermomechanical parameters was developed in this study by combining the self‐developed heat‐resistant grids and the sampling moiré method. First, several factors, including the oblique angle of the grids, image noise and thermomechanical coupling phenomena, were studied through numerical experiments to analyse their influences on the identification accuracy. Then, an optimised identification strategy was established. Finally, the thermomechanical parameters of Ni‐based polycrystalline and single‐crystal superalloys were successfully identified and comparatively studied. The identification results demonstrate that the proposed method is highly accurate and robust. This research will provide an effective way to accurately characterise the multiple parameters of superalloys at high temperatures.
{"title":"Identification of thermomechanical parameters based on the virtual fields method combined with the sampling moiré method","authors":"Yangyang Li, H. Xie","doi":"10.1111/str.12429","DOIUrl":"https://doi.org/10.1111/str.12429","url":null,"abstract":"Thermomechanical parameters are important indicators for evaluating the mechanical properties of superalloys and generally include the coefficients of stiffness and thermal expansion at high temperatures. At present, there are few methods for simultaneously characterising the thermomechanical parameters of superalloys, especially single‐crystal superalloys. To satisfy the demand for simultaneously identifying the thermomechanical parameters of orthotropic superalloys, an optimised virtual fields method for decoupling the thermomechanical parameters was developed in this study by combining the self‐developed heat‐resistant grids and the sampling moiré method. First, several factors, including the oblique angle of the grids, image noise and thermomechanical coupling phenomena, were studied through numerical experiments to analyse their influences on the identification accuracy. Then, an optimised identification strategy was established. Finally, the thermomechanical parameters of Ni‐based polycrystalline and single‐crystal superalloys were successfully identified and comparatively studied. The identification results demonstrate that the proposed method is highly accurate and robust. This research will provide an effective way to accurately characterise the multiple parameters of superalloys at high temperatures.","PeriodicalId":51176,"journal":{"name":"Strain","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48913882","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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