Digital image correlation (DIC) methods initially were developed in the early 1980s to simplify basic in-plane laboratory experiments, modified in the 1990s to obtain full three-dimensional surface displacement and motion measurements on curved or planar specimens and extended to interior measurements at the end of the last millennium. The enclosed article provides a brief description of the various digital image correlation methods, followed by a personal perspective regarding recent and future developments utilizing DIC measurements.
{"title":"Experimental Measurements Using Digital Image Correlation Methods: Brief Background and Perspective on Future Developments","authors":"M. Sutton","doi":"10.1115/1.4055471","DOIUrl":"https://doi.org/10.1115/1.4055471","url":null,"abstract":"\u0000 Digital image correlation (DIC) methods initially were developed in the early 1980s to simplify basic in-plane laboratory experiments, modified in the 1990s to obtain full three-dimensional surface displacement and motion measurements on curved or planar specimens and extended to interior measurements at the end of the last millennium. The enclosed article provides a brief description of the various digital image correlation methods, followed by a personal perspective regarding recent and future developments utilizing DIC measurements.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48302196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We use 3D printing to manufacture lattices with uniform and graded relative density, made from a composite parent material comprising a nylon matrix reinforced by short carbon fibres. The elastic-plastic compressive response of these solids is measured up to their densification regime. Data from experiments on the lattices with uniform relative density is used to deduce the dependence of their elastic-plastic homogenised constitutive response on their relative density, in the range 0.2-0.8. This data is used to calibrate Finite Element (FE) simulations of the compressive response of Functionally Graded Lattices (FGLs), which are found in good agreement with the corresponding measurements, capturing the salient features of the measured stress versus strain responses. This exercise is repeated for two lattice topologies (body-centred cubic and Schwarz-P). The phenomenological constitutive models produced in this study can be used in topology optimisation to maximise the performance of 3D printed FGLs components in terms of stiffness, strength or energy absorption.
{"title":"Predictions of the Elastic-Plastic Compressive Response of Functionally Graded Polymeric Composite Lattices Manufactured by 3D Printing","authors":"J. Plocher, V. Tagarielli, A. Panesar","doi":"10.1115/1.4055472","DOIUrl":"https://doi.org/10.1115/1.4055472","url":null,"abstract":"\u0000 We use 3D printing to manufacture lattices with uniform and graded relative density, made from a composite parent material comprising a nylon matrix reinforced by short carbon fibres. The elastic-plastic compressive response of these solids is measured up to their densification regime. Data from experiments on the lattices with uniform relative density is used to deduce the dependence of their elastic-plastic homogenised constitutive response on their relative density, in the range 0.2-0.8. This data is used to calibrate Finite Element (FE) simulations of the compressive response of Functionally Graded Lattices (FGLs), which are found in good agreement with the corresponding measurements, capturing the salient features of the measured stress versus strain responses. This exercise is repeated for two lattice topologies (body-centred cubic and Schwarz-P). The phenomenological constitutive models produced in this study can be used in topology optimisation to maximise the performance of 3D printed FGLs components in terms of stiffness, strength or energy absorption.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42077190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Matthew R. Northam, Q. Fouliard, L. Rossmann, Jun-Sang Park, P. Kenesei, J. Almer, V. Viswanathan, B. Harder, S. Raghavan
The current standard application method for thermal barrier coatings (TBCs) on turbine blades for jet engines is electron-beam physical vapor deposition (EB-PVD) due to its high strain tolerance and low thermal conductivity. An emerging deposition method, plasma-spray physical vapor deposition (PS- PVD), presents an opportunity for a tailorable microstructure, and non-line- of-sight deposition that is faster and less expensive. To compare the lifetime behavior of both PS-PVD and EB-PVD coatings, samples subjected to 300 and 600 thermal cycles were measured during a 1-hour thermal cycle to de- termine the strains, which were converted to stress, in the thermally grown oxide (TGO) layer of the TBCs using synchrotron X-ray diffraction (XRD). Room temperature XRD measurements indicated among samples that PS- PVD coatings experienced greater variation in in-plane room temperature strain in the TGO after cycling than the EB-PVD coatings. In-situ XRD measurements indicated similar high-temperature strain and no spallation after 600 thermal cycles for both coatings. Microscopy imaging after cycling showed greater rumpling in PS-PVD coatings that led to different failure modes between the two coatings’ TGO layer. The tailorability of PS-PVD coatings allows for adjustments in the processing parameters to improve their overall performance after aging and bridge the differences between the two deposition methods.
{"title":"Thermally Grown Oxide Stress in PS-PVD and EB-PVD Thermal Barrier Coatings Observed at Various Lifetimes via Synchrotron X-ray Diffraction","authors":"Matthew R. Northam, Q. Fouliard, L. Rossmann, Jun-Sang Park, P. Kenesei, J. Almer, V. Viswanathan, B. Harder, S. Raghavan","doi":"10.1115/1.4055398","DOIUrl":"https://doi.org/10.1115/1.4055398","url":null,"abstract":"\u0000 The current standard application method for thermal barrier coatings (TBCs) on turbine blades for jet engines is electron-beam physical vapor deposition (EB-PVD) due to its high strain tolerance and low thermal conductivity. An emerging deposition method, plasma-spray physical vapor deposition (PS- PVD), presents an opportunity for a tailorable microstructure, and non-line- of-sight deposition that is faster and less expensive. To compare the lifetime behavior of both PS-PVD and EB-PVD coatings, samples subjected to 300 and 600 thermal cycles were measured during a 1-hour thermal cycle to de- termine the strains, which were converted to stress, in the thermally grown oxide (TGO) layer of the TBCs using synchrotron X-ray diffraction (XRD). Room temperature XRD measurements indicated among samples that PS- PVD coatings experienced greater variation in in-plane room temperature strain in the TGO after cycling than the EB-PVD coatings. In-situ XRD measurements indicated similar high-temperature strain and no spallation after 600 thermal cycles for both coatings. Microscopy imaging after cycling showed greater rumpling in PS-PVD coatings that led to different failure modes between the two coatings’ TGO layer. The tailorability of PS-PVD coatings allows for adjustments in the processing parameters to improve their overall performance after aging and bridge the differences between the two deposition methods.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42423965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The shear failure behaviors of U71Mn are investigated by quasi-static and dynamic compression tests utilizing two different hat-shaped specimens S1 which combines shear and compressive stress states and S2 which combines shear and tensile stress states. A split Hopkinson pressure bar is used to acquire shear stress-strain curves at various initial temperatures and shear strain rates, and it is found that a lower shear strain rate is observed in hat-shaped specimen S1 than that in hat-shaped specimen S2 under the same impact pressure. Scanning electron microscopy is employed for observing the microstructures of specimens. The results indicate that the hat-shaped specimen S1 is difficult to form voids and dimples. Moreover, as far as the hat-shaped specimen S2 is concerned, the number of voids reduces with the rising shear strain rate, and no voids appear on the fracture surface at the shear strain rate of 36000 s−1. Furthermore, the creation of voids is aided by a rise in initial temperature. The factors affecting the formation of adiabatic shear bands are explored based on the numerical simulation, which suggests that the magnitude of the temperature gradient plays a crucial role in the generation of adiabatic shear bands.
{"title":"Comparative Studies on Shear Failure Behaviors of U71Mn Rail Steel at High Strain Rates Using Hat-Shaped Specimens","authors":"Jianbing Wu, Zhan K. Wang","doi":"10.1115/1.4055227","DOIUrl":"https://doi.org/10.1115/1.4055227","url":null,"abstract":"\u0000 The shear failure behaviors of U71Mn are investigated by quasi-static and dynamic compression tests utilizing two different hat-shaped specimens S1 which combines shear and compressive stress states and S2 which combines shear and tensile stress states. A split Hopkinson pressure bar is used to acquire shear stress-strain curves at various initial temperatures and shear strain rates, and it is found that a lower shear strain rate is observed in hat-shaped specimen S1 than that in hat-shaped specimen S2 under the same impact pressure. Scanning electron microscopy is employed for observing the microstructures of specimens. The results indicate that the hat-shaped specimen S1 is difficult to form voids and dimples. Moreover, as far as the hat-shaped specimen S2 is concerned, the number of voids reduces with the rising shear strain rate, and no voids appear on the fracture surface at the shear strain rate of 36000 s−1. Furthermore, the creation of voids is aided by a rise in initial temperature. The factors affecting the formation of adiabatic shear bands are explored based on the numerical simulation, which suggests that the magnitude of the temperature gradient plays a crucial role in the generation of adiabatic shear bands.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43264765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A comprehensive assessment of interstitial hydrogen on the elastic behavior across different metals (Al, Ni, Fe, Nb, Ti, and Zr) was carried out using first-principles calculations. The volumetric strain introduced by interstitial hydrogen had a key role in the observed variation in elastic constants. However, in Nb, Ti and Zr, the host and hydrogen atoms interact strongly that had a significant contribution towards the variation in elastic response due to the presence of hydrogen. The addition of hydrogen reduced the resistance to shear deformation along respective active slip systems for all the metals, except Nb. Similarly, the homogenized macroscopic approximation of Young's and shear moduli also demonstrated a drop with increasing hydrogen concentration across all the metals, apart from Nb. Finally, these findings accurately quantify the variation in elastic behavior of various metals when exposed to a hydrogen rich environment.
{"title":"Effect of Interstitial Hydrogen on Elastic Behavior of Metals: an Ab-Initio Study","authors":"P. Kumar, I. Adlakha","doi":"10.1115/1.4055097","DOIUrl":"https://doi.org/10.1115/1.4055097","url":null,"abstract":"\u0000 A comprehensive assessment of interstitial hydrogen on the elastic behavior across different metals (Al, Ni, Fe, Nb, Ti, and Zr) was carried out using first-principles calculations. The volumetric strain introduced by interstitial hydrogen had a key role in the observed variation in elastic constants. However, in Nb, Ti and Zr, the host and hydrogen atoms interact strongly that had a significant contribution towards the variation in elastic response due to the presence of hydrogen. The addition of hydrogen reduced the resistance to shear deformation along respective active slip systems for all the metals, except Nb. Similarly, the homogenized macroscopic approximation of Young's and shear moduli also demonstrated a drop with increasing hydrogen concentration across all the metals, apart from Nb. Finally, these findings accurately quantify the variation in elastic behavior of various metals when exposed to a hydrogen rich environment.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42574718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qiutao Fu, Di Li, Hui Song, Xingfeng Liu, Jiachuan Xu, Ning Jiang
Advanced High Strength Steel (AHSS) are increasingly used in the automotive industry due to its higher strength and lower weight. The traditional forming limit criterion cannot accurately predict the unique shear fracture of AHSS, so great efforts have been made to develop failure criteria that can predict shear fracture. In this paper, a series of tensile and shear tests for four steel sheets of AHSS are designed, the stress triaxiality and equivalent strain are measured and solved, and the correlation between them and the performance parameters of steel sheets K and n is studied. In order to study the relationship between stress triaxiality and equivalent strain in the range of low stress triaxiality, the Hill'48 orthotropic model and MMC fracture model were used to establish tensile and shear fracture models of four dual-phase steels. Simulate and study the plastic fracture of AHSS. Solving the relevant parameters enriches the stress triaxiality of the four steel types, and establishes the relationship between the stress triaxiality and the equivalent strain, and verifies its correctness through tensile and bending tests and simulations. The results show that MMC can accurately predict the fracture of these four dual-phase steels, and the quantitative relationship between stress triaxiality and equivalent strain of the four dual-phase steels in the low-stress triaxiality range 0-0.3 is similar, which can be established and expressed by the performance parameters of each steel type.
{"title":"Shear Fracture Criterion of Advanced High-Strength Steel Based on Stress Triaxiality and Equivalent Strain","authors":"Qiutao Fu, Di Li, Hui Song, Xingfeng Liu, Jiachuan Xu, Ning Jiang","doi":"10.1115/1.4055096","DOIUrl":"https://doi.org/10.1115/1.4055096","url":null,"abstract":"\u0000 Advanced High Strength Steel (AHSS) are increasingly used in the automotive industry due to its higher strength and lower weight. The traditional forming limit criterion cannot accurately predict the unique shear fracture of AHSS, so great efforts have been made to develop failure criteria that can predict shear fracture. In this paper, a series of tensile and shear tests for four steel sheets of AHSS are designed, the stress triaxiality and equivalent strain are measured and solved, and the correlation between them and the performance parameters of steel sheets K and n is studied. In order to study the relationship between stress triaxiality and equivalent strain in the range of low stress triaxiality, the Hill'48 orthotropic model and MMC fracture model were used to establish tensile and shear fracture models of four dual-phase steels. Simulate and study the plastic fracture of AHSS. Solving the relevant parameters enriches the stress triaxiality of the four steel types, and establishes the relationship between the stress triaxiality and the equivalent strain, and verifies its correctness through tensile and bending tests and simulations. The results show that MMC can accurately predict the fracture of these four dual-phase steels, and the quantitative relationship between stress triaxiality and equivalent strain of the four dual-phase steels in the low-stress triaxiality range 0-0.3 is similar, which can be established and expressed by the performance parameters of each steel type.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44435862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The thermally-driven evolution of β-phase (Al3Mg2) and its impact on strength is explored for three different producers of aluminum alloy 5083-H131 used in armor applications. Specimens were exposed to 100°C air for periods of up to 30 days. Through a combination of optical microscopy and computational image analysis, the extent of matrix β and grain boundary β in the microstructure was assessed. Quasi-static tensile testing was also used to measure strength as a function of exposure time. It was found that a degradation in yield strength strongly correlates with the rapid emergence of matrix β-phase and not slowly evolving grain boundary β networks typical of a sensitized microstructure. The decrease in yield strength is attributed to the loss of the solid solution strengthening via matrix β-phase precipitation. This suggests that field exposure to solar radiation, ambient air, or engine/exhaust heat could lead to a loss in the level of ballistic protection afforded by the alloy even without a sensitized condition.
{"title":"Strength Degradation in AA5083 Armor Plate after Exposure to Elevated Temperatures","authors":"Scott D. Kasen, D. Tubbs","doi":"10.1115/1.4055052","DOIUrl":"https://doi.org/10.1115/1.4055052","url":null,"abstract":"\u0000 The thermally-driven evolution of β-phase (Al3Mg2) and its impact on strength is explored for three different producers of aluminum alloy 5083-H131 used in armor applications. Specimens were exposed to 100°C air for periods of up to 30 days. Through a combination of optical microscopy and computational image analysis, the extent of matrix β and grain boundary β in the microstructure was assessed. Quasi-static tensile testing was also used to measure strength as a function of exposure time. It was found that a degradation in yield strength strongly correlates with the rapid emergence of matrix β-phase and not slowly evolving grain boundary β networks typical of a sensitized microstructure. The decrease in yield strength is attributed to the loss of the solid solution strengthening via matrix β-phase precipitation. This suggests that field exposure to solar radiation, ambient air, or engine/exhaust heat could lead to a loss in the level of ballistic protection afforded by the alloy even without a sensitized condition.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46490465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhige Wang, J. Dirrenberger, P. Lapouge, S. Dubent, Hamza A. Jabir, V. Michel
Carburization assisted by laser processing is a promising method to strengthen metallic materials. Direct laser beam carburization is implemented for the first time on thin AISI 430 ferritic stainless steel sheets with graphite coating under different conditions. Microstructural morphology, phase constitution, carbon content, microhardness and tensile behavior are investigated to evaluate laser carburization effect. The carburized zone presents different morphologies according to linear energy density of laser beam. The least carbon content is around 0.4 wt% in the carburized zone where austenite becomes the leading phase. Delta ferrite is found in cellular carburized area, which resembles to a duplex microstructure. Hardness of carburized zone has been at least increased by 130%. And the yield strength and ultimate tensile strength of a fully carburized sample can be increased up by respectively 90% and 85 %. This hardening effect is driven by the precipitation of carbides formed during solidification offering pinning points for dislocations and grain boundaries. These improvements could be useful to modify locally ferritic stainless steel to meet industrial needs such as wear-resistant surface.
{"title":"Microstructure Evolution and Mechanical Properties of AISI 430 Ferritic Stainless Steel Strengthened through Laser Carburization","authors":"Zhige Wang, J. Dirrenberger, P. Lapouge, S. Dubent, Hamza A. Jabir, V. Michel","doi":"10.1115/1.4055025","DOIUrl":"https://doi.org/10.1115/1.4055025","url":null,"abstract":"\u0000 Carburization assisted by laser processing is a promising method to strengthen metallic materials. Direct laser beam carburization is implemented for the first time on thin AISI 430 ferritic stainless steel sheets with graphite coating under different conditions. Microstructural morphology, phase constitution, carbon content, microhardness and tensile behavior are investigated to evaluate laser carburization effect. The carburized zone presents different morphologies according to linear energy density of laser beam. The least carbon content is around 0.4 wt% in the carburized zone where austenite becomes the leading phase. Delta ferrite is found in cellular carburized area, which resembles to a duplex microstructure. Hardness of carburized zone has been at least increased by 130%. And the yield strength and ultimate tensile strength of a fully carburized sample can be increased up by respectively 90% and 85 %. This hardening effect is driven by the precipitation of carbides formed during solidification offering pinning points for dislocations and grain boundaries. These improvements could be useful to modify locally ferritic stainless steel to meet industrial needs such as wear-resistant surface.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47849257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Johnson-Cook (JC) flow stress model can simply express the strain rate and temperature dependencies of the flow stress. We previously proposed a concept of simple identification method for material constants in the JC model associated with the strain-rate and temperature sensitivities (JC parameters C and m) at high strain rates. However, several issues still exist in our method for practical use. In this study, we modified our method to identify both the JC parameters C and m. The fundamental concept was formulated based on the requirement that the normalized indentation depths obtained from the ball impact and instrumented ball indentation tests are equal to each other. In addition, the conversion factor was derived to transfer from the impact velocity to the strain rate. The ball indentation and impact analyses based on a finite element method were conducted to verify the established method. The analysis results obtained under idealized conditions demonstrated that C and m can be accurately identified using the established method, even at exceeding 10000 1/s. Changes in the radius of impactor are more effective in obtaining different strain rates than changes in the impact velocity, because the identification accuracy can be ensured at lower than 200 m/s.
{"title":"Identification Method for Material Constants in Johnson-Cook Model Associated with Strain-Rate and Temperature Sensitivities Using Ball Impact and Indentation Tests","authors":"Kiyohiro Ito","doi":"10.1115/1.4054957","DOIUrl":"https://doi.org/10.1115/1.4054957","url":null,"abstract":"\u0000 The Johnson-Cook (JC) flow stress model can simply express the strain rate and temperature dependencies of the flow stress. We previously proposed a concept of simple identification method for material constants in the JC model associated with the strain-rate and temperature sensitivities (JC parameters C and m) at high strain rates. However, several issues still exist in our method for practical use. In this study, we modified our method to identify both the JC parameters C and m. The fundamental concept was formulated based on the requirement that the normalized indentation depths obtained from the ball impact and instrumented ball indentation tests are equal to each other. In addition, the conversion factor was derived to transfer from the impact velocity to the strain rate. The ball indentation and impact analyses based on a finite element method were conducted to verify the established method. The analysis results obtained under idealized conditions demonstrated that C and m can be accurately identified using the established method, even at exceeding 10000 1/s. Changes in the radius of impactor are more effective in obtaining different strain rates than changes in the impact velocity, because the identification accuracy can be ensured at lower than 200 m/s.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44452432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Seidt, Chung‐Kyu Park, Murat Buyuk, R. Lowe, Leyu Wang, K. Carney, P. Dubois, A. Gilat, C. Kan
This paper investigates the influence of stress state on the equivalent plastic fracture strain in 2024-T351 aluminum alloy. Eighteen unique stress states at failure – with triaxialities ranging from 0.388 (compressive) to -0.891 (tensile) and Lode parameters ranging from -0.978 to 1.000 – are explored through mechanical experiments on 2024-T351 aluminum specimens with various geometries under multiple loading conditions. These include tension tests of plane stress (thin), plane strain (thick), and axisymmetric specimens, as well as pure shear and combined axial-torsional loading on thin-walled tubes. Using a hybrid numerical-experimental approach, the dependence of fracture strain on stress triaxiality and Lode parameter is quantified for each experiment. Fracture strains are measured using three-dimensional digital image correlation. Equivalent plastic fracture strain for 2024-T351 generally increases with stress triaxiality (moving toward a more compressive state). Fracture strain decreases modestly as Lode parameter decreases from 1 to 0, although there is a significant increase in ductility as Lode parameter decreases below -0.8. Compression-torsion tests extend the data's stress-space coverage well into the compressive triaxiality region (up to 0.388) and to Lode parameters approaching -1. This experimental program provides the most extensive set of ductile fracture data from a single 12.7-mm-thick 2024-T351 aluminum plate in the literature. These data can be used to calibrate ductile fracture models used in finite element simulations of dynamic events such as bird strikes, automotive collisions, and debris containment.
{"title":"An Experimental Investigation of the Influence of the State of Stress on the Ductile Fracture of 2024-T351 Aluminum","authors":"J. Seidt, Chung‐Kyu Park, Murat Buyuk, R. Lowe, Leyu Wang, K. Carney, P. Dubois, A. Gilat, C. Kan","doi":"10.1115/1.4054895","DOIUrl":"https://doi.org/10.1115/1.4054895","url":null,"abstract":"\u0000 This paper investigates the influence of stress state on the equivalent plastic fracture strain in 2024-T351 aluminum alloy. Eighteen unique stress states at failure – with triaxialities ranging from 0.388 (compressive) to -0.891 (tensile) and Lode parameters ranging from -0.978 to 1.000 – are explored through mechanical experiments on 2024-T351 aluminum specimens with various geometries under multiple loading conditions. These include tension tests of plane stress (thin), plane strain (thick), and axisymmetric specimens, as well as pure shear and combined axial-torsional loading on thin-walled tubes. Using a hybrid numerical-experimental approach, the dependence of fracture strain on stress triaxiality and Lode parameter is quantified for each experiment. Fracture strains are measured using three-dimensional digital image correlation. Equivalent plastic fracture strain for 2024-T351 generally increases with stress triaxiality (moving toward a more compressive state). Fracture strain decreases modestly as Lode parameter decreases from 1 to 0, although there is a significant increase in ductility as Lode parameter decreases below -0.8. Compression-torsion tests extend the data's stress-space coverage well into the compressive triaxiality region (up to 0.388) and to Lode parameters approaching -1. This experimental program provides the most extensive set of ductile fracture data from a single 12.7-mm-thick 2024-T351 aluminum plate in the literature. These data can be used to calibrate ductile fracture models used in finite element simulations of dynamic events such as bird strikes, automotive collisions, and debris containment.","PeriodicalId":15700,"journal":{"name":"Journal of Engineering Materials and Technology-transactions of The Asme","volume":" ","pages":""},"PeriodicalIF":1.2,"publicationDate":"2022-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43489451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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