Hideo Takizawa - Academia.edu (original) (raw)
Papers by Hideo Takizawa
Journal of the Society of Materials Science, Japan
Journal of the Japan Society for Technology of Plasticity, 2019
In this study, the anisotropic plastic properties of perforated sheet metal with regular staggere... more In this study, the anisotropic plastic properties of perforated sheet metal with regular staggered holes were analyzed by the homogenization method. A hexagonal unit cell with periodic boundary conditions was selected for the analysis. To validate the analysis results, comparisons were made with the experimental results obtained from a uniaxial tensile test. The analyzed stress-strain curves obtained from directional tensile tests match the corresponding experimental stress-strain curves. The in-plane variations of the analyzed r-values also agree qualitatively with the experimental results. In the biaxial tensile test, the macro yield surface was evaluated as an equal plastic work contour in the proportional stress path. Obtained results indicate differential (anisotropic) hardening and slight tension-compression asymmetry of the subsequent macro yield surface. In the case of the proportional loading path, the associated flow rule (AFR) for the initial and subsequent yield surfaces is applicable. However, regarding the non-proportional loading path, the AFR may not be applicable in certain cases because the distribution patterns of the strain rate around the holes depend on the history of local work hardening.
Journal of Japan Institute of Light Metals
Yield surfaces of A5052 aluminum alloy sheets with different tempers are modeled by the simplifie... more Yield surfaces of A5052 aluminum alloy sheets with different tempers are modeled by the simplified identification method using the circumscribing polygon. In this method, a polygon circumscribing the equal plastic work contour is determined by uniaxial tensile, equal biaxial tensile and plane strain tensile tests. Anisotropic yield surfaces of A5052 aluminum alloy sheet are modeled by Yld2000-2d (Barlat et al., 2003) and Yld2004-18p (Barlat et al., 2005) yield functions. Both yield functions can express the inscribed curves of the polygons. The modeled yield surfaces of A5052-O agree with the stress points of the equal plastic work contours measured by the reliable bi-axial tensile tests. The proposed method to identify the yield function is effective for aluminum sheet metal. On the other hand, the two identified yield functions show different in-plane plastic anisotropy in the tension-compression combined stress state. To examine the suitability of identified models, the experiments and numerical analyses of the deep drawing tests are carried out. Comparing the experimental and analyzed results, the predicted ear height of drawn cup using the Yld2004-18p yield function agree with experimental results qualitatively. But the prediction of the ear using the Yld2000-2d cannot express the tendency of the experimental one.
Journal of Physics: Conference Series, 2018
International Journal of Mechanical Sciences, 2017
Aming at the future applications of a lattice structure manufactured by selective laser sintering... more Aming at the future applications of a lattice structure manufactured by selective laser sintering for bone scaffold in the biomedical field, by putting highlight on the possible imperfections influenced by different manufacturing strategies, a numerical prediction method was studied and compared with compressive test results. To consider the geometrical imperfections as well
Journal of Physics: Conference Series, 2016
In-plane biaxial tension and combined tension-compression tests are carried out for AA3104 alumin... more In-plane biaxial tension and combined tension-compression tests are carried out for AA3104 aluminum alloy sheets. Linear stress paths are applied to cruciform specimens to measure the contours of plastic work in the stress space and the directions of plastic strain rates at each stress path. Coefficientsand exponent of the Yld2000-2d yield function are determined to minimize the mean square error of the analytical yield locus from a measured work contour. The values of the weighting coefficients in the evaluation of the error are varied to check the effect of a specific stress state on the earing behavior. The effects of the combinations of the weighting coefficients on the accuracy of earing prediction in the cup drawing process are discussed.
Superalloys 2004 (Tenth International Symposium), 2004
Continuous improvements of properties for individual parts are indispensable for perpetual develo... more Continuous improvements of properties for individual parts are indispensable for perpetual development of aircraft engines. Concerning casing and seal, simulation of ring rolling process is one of the most attractive tools to reduce the cost and time and to improve the properties and the reliability at the same time. In order to obtain both practical prediction accuracy and acceptable computation time from industrial standpoint, the refined partial three-dimensional deformation model was proposed. Moreover the relationship between microstructure evolution and various parameters regarding to Waspaloy* was evaluated and microstructure prediction models were developed. Constructed microstructure prediction models were coupled to the finite element analyzing system to estimate mean grain diameter and fraction of recrystallization in addition to general output e.g. temperature, strain. The effectiveness of proposed prediction system as a process design tool was confirmed through multi compression test and production of actual casing that had extremely complicated near-net-shape.
Journal of Physics: Conference Series, 2018
Arkansas has had a long and storied history related to its forests and forestry. Ever since its a... more Arkansas has had a long and storied history related to its forests and forestry. Ever since its acquisition in the Louisiana Purchase, timber has played a large role in the socioeconomic development of this state. In the 1880s, it was estimated that Arkansas had about 13 million ha (32 million ac) of forests and several hundred billion board feet of timber, numbers that fell dramatically as commercial lumbering spread across the state. After reaching historic lows in forest coverage and volume around the end of World War II, better conservation measures and the widespread implementation of sustainable forestry and fire suppression has allowed for some recovery of forested cover (now stabilized at about 7.3 million ha [18 million ac]) and a steady increase in timber volume (currently estimated at over 0.8 billion m 3 [27 billion ft 3 ]). Over one-third of the timber volume in Arkansas is pine (Pinus spp.), a number that is expected to increase as pine plantations continue to replace natural-origin pine and pine-hardwood stands. Recent changes in ownership, increased management intensity, and threats to the health of Arkansas timberlands will continue to challenge foresters well into the future.
Journal of Physics: Conference Series, Jul 1, 2018
Arkansas has had a long and storied history related to its forests and forestry. Ever since its a... more Arkansas has had a long and storied history related to its forests and forestry. Ever since its acquisition in the Louisiana Purchase, timber has played a large role in the socioeconomic development of this state. In the 1880s, it was estimated that Arkansas had about 13 million ha (32 million ac) of forests and several hundred billion board feet of timber, numbers that fell dramatically as commercial lumbering spread across the state. After reaching historic lows in forest coverage and volume around the end of World War II, better conservation measures and the widespread implementation of sustainable forestry and fire suppression has allowed for some recovery of forested cover (now stabilized at about 7.3 million ha [18 million ac]) and a steady increase in timber volume (currently estimated at over 0.8 billion m 3 [27 billion ft 3 ]). Over one-third of the timber volume in Arkansas is pine (Pinus spp.), a number that is expected to increase as pine plantations continue to replace natural-origin pine and pine-hardwood stands. Recent changes in ownership, increased management intensity, and threats to the health of Arkansas timberlands will continue to challenge foresters well into the future.
Journal of Physics: Conference Series, Jul 1, 2018
Journal of the Society of Materials Science, Japan
In order to discuss the quality assurance of additively manufactured lattice structure made by al... more In order to discuss the quality assurance of additively manufactured lattice structure made by aluminum alloy (AlSi10Mg) using 3D printing technology or selective laser sintering technique, compression test, micro-CT imaging and finite element analysis were carried out. The specimens were manufactured by 2 printing service companies with different expertise, which led to the choice of different process parameters such as the building direction, support structure, powder bed temperature and laser scanning speed. The largely scattered compressive peak loads were in good linear positive correlation with the weight, which is the easiest and convenient index for the quality assurance. On the other hand, the apparent density was almost the same. The reason why the weight of the products was largely scattered was investigated by micro-CT image analysis and finite element analysis. Also by comparison with the CAD data, the influence of manufacturer-dependent process parameters on the strength was discussed.
Journal of the Japan Society for Technology of Plasticity
An experimental procedure for the hot compression test for Ni-based alloy was proposed and evalua... more An experimental procedure for the hot compression test for Ni-based alloy was proposed and evaluated in order to obtain an appropriate stress-strain curve for numerical analysis. The effect of various parameters, i.e., top and bottom shapes of specimen, lubricant and jig/tool, on the deformation tendency was systematically studied. Ni-based alloy (CMSX-4), which has a higher strength than the specimen, was used as die for preventing temperature gradient. This improved the uniformity of temperature distribution in the specimen. The combination of a specimen having concentric circles on the end surface and a glass sheet as lubricant was the most appropriate to gain stable and low-friction condition of the specimen end. The proposed procedure of the hot compression test is applicable for the temperature range of 1173-1423 K and strain rate range of 0.01-5 s-1. The effectiveness of the obtained stress-strain curve was discussed from the viewpoint of the value and tendency of characteristic features observed in the flow stress curve. The maximum stress exhibited normal temperature and strain rate dependence. Related activation energy for deformation was similar in value to those in other reports.
Journal of the Japan Society for Technology of Plasticity, 2014
Journal of the Society of Materials Science, Japan
Journal of the Japan Society for Technology of Plasticity, 2019
In this study, the anisotropic plastic properties of perforated sheet metal with regular staggere... more In this study, the anisotropic plastic properties of perforated sheet metal with regular staggered holes were analyzed by the homogenization method. A hexagonal unit cell with periodic boundary conditions was selected for the analysis. To validate the analysis results, comparisons were made with the experimental results obtained from a uniaxial tensile test. The analyzed stress-strain curves obtained from directional tensile tests match the corresponding experimental stress-strain curves. The in-plane variations of the analyzed r-values also agree qualitatively with the experimental results. In the biaxial tensile test, the macro yield surface was evaluated as an equal plastic work contour in the proportional stress path. Obtained results indicate differential (anisotropic) hardening and slight tension-compression asymmetry of the subsequent macro yield surface. In the case of the proportional loading path, the associated flow rule (AFR) for the initial and subsequent yield surfaces is applicable. However, regarding the non-proportional loading path, the AFR may not be applicable in certain cases because the distribution patterns of the strain rate around the holes depend on the history of local work hardening.
Journal of Japan Institute of Light Metals
Yield surfaces of A5052 aluminum alloy sheets with different tempers are modeled by the simplifie... more Yield surfaces of A5052 aluminum alloy sheets with different tempers are modeled by the simplified identification method using the circumscribing polygon. In this method, a polygon circumscribing the equal plastic work contour is determined by uniaxial tensile, equal biaxial tensile and plane strain tensile tests. Anisotropic yield surfaces of A5052 aluminum alloy sheet are modeled by Yld2000-2d (Barlat et al., 2003) and Yld2004-18p (Barlat et al., 2005) yield functions. Both yield functions can express the inscribed curves of the polygons. The modeled yield surfaces of A5052-O agree with the stress points of the equal plastic work contours measured by the reliable bi-axial tensile tests. The proposed method to identify the yield function is effective for aluminum sheet metal. On the other hand, the two identified yield functions show different in-plane plastic anisotropy in the tension-compression combined stress state. To examine the suitability of identified models, the experiments and numerical analyses of the deep drawing tests are carried out. Comparing the experimental and analyzed results, the predicted ear height of drawn cup using the Yld2004-18p yield function agree with experimental results qualitatively. But the prediction of the ear using the Yld2000-2d cannot express the tendency of the experimental one.
Journal of Physics: Conference Series, 2018
International Journal of Mechanical Sciences, 2017
Aming at the future applications of a lattice structure manufactured by selective laser sintering... more Aming at the future applications of a lattice structure manufactured by selective laser sintering for bone scaffold in the biomedical field, by putting highlight on the possible imperfections influenced by different manufacturing strategies, a numerical prediction method was studied and compared with compressive test results. To consider the geometrical imperfections as well
Journal of Physics: Conference Series, 2016
In-plane biaxial tension and combined tension-compression tests are carried out for AA3104 alumin... more In-plane biaxial tension and combined tension-compression tests are carried out for AA3104 aluminum alloy sheets. Linear stress paths are applied to cruciform specimens to measure the contours of plastic work in the stress space and the directions of plastic strain rates at each stress path. Coefficientsand exponent of the Yld2000-2d yield function are determined to minimize the mean square error of the analytical yield locus from a measured work contour. The values of the weighting coefficients in the evaluation of the error are varied to check the effect of a specific stress state on the earing behavior. The effects of the combinations of the weighting coefficients on the accuracy of earing prediction in the cup drawing process are discussed.
Superalloys 2004 (Tenth International Symposium), 2004
Continuous improvements of properties for individual parts are indispensable for perpetual develo... more Continuous improvements of properties for individual parts are indispensable for perpetual development of aircraft engines. Concerning casing and seal, simulation of ring rolling process is one of the most attractive tools to reduce the cost and time and to improve the properties and the reliability at the same time. In order to obtain both practical prediction accuracy and acceptable computation time from industrial standpoint, the refined partial three-dimensional deformation model was proposed. Moreover the relationship between microstructure evolution and various parameters regarding to Waspaloy* was evaluated and microstructure prediction models were developed. Constructed microstructure prediction models were coupled to the finite element analyzing system to estimate mean grain diameter and fraction of recrystallization in addition to general output e.g. temperature, strain. The effectiveness of proposed prediction system as a process design tool was confirmed through multi compression test and production of actual casing that had extremely complicated near-net-shape.
Journal of Physics: Conference Series, 2018
Arkansas has had a long and storied history related to its forests and forestry. Ever since its a... more Arkansas has had a long and storied history related to its forests and forestry. Ever since its acquisition in the Louisiana Purchase, timber has played a large role in the socioeconomic development of this state. In the 1880s, it was estimated that Arkansas had about 13 million ha (32 million ac) of forests and several hundred billion board feet of timber, numbers that fell dramatically as commercial lumbering spread across the state. After reaching historic lows in forest coverage and volume around the end of World War II, better conservation measures and the widespread implementation of sustainable forestry and fire suppression has allowed for some recovery of forested cover (now stabilized at about 7.3 million ha [18 million ac]) and a steady increase in timber volume (currently estimated at over 0.8 billion m 3 [27 billion ft 3 ]). Over one-third of the timber volume in Arkansas is pine (Pinus spp.), a number that is expected to increase as pine plantations continue to replace natural-origin pine and pine-hardwood stands. Recent changes in ownership, increased management intensity, and threats to the health of Arkansas timberlands will continue to challenge foresters well into the future.
Journal of Physics: Conference Series, Jul 1, 2018
Arkansas has had a long and storied history related to its forests and forestry. Ever since its a... more Arkansas has had a long and storied history related to its forests and forestry. Ever since its acquisition in the Louisiana Purchase, timber has played a large role in the socioeconomic development of this state. In the 1880s, it was estimated that Arkansas had about 13 million ha (32 million ac) of forests and several hundred billion board feet of timber, numbers that fell dramatically as commercial lumbering spread across the state. After reaching historic lows in forest coverage and volume around the end of World War II, better conservation measures and the widespread implementation of sustainable forestry and fire suppression has allowed for some recovery of forested cover (now stabilized at about 7.3 million ha [18 million ac]) and a steady increase in timber volume (currently estimated at over 0.8 billion m 3 [27 billion ft 3 ]). Over one-third of the timber volume in Arkansas is pine (Pinus spp.), a number that is expected to increase as pine plantations continue to replace natural-origin pine and pine-hardwood stands. Recent changes in ownership, increased management intensity, and threats to the health of Arkansas timberlands will continue to challenge foresters well into the future.
Journal of Physics: Conference Series, Jul 1, 2018
Journal of the Society of Materials Science, Japan
In order to discuss the quality assurance of additively manufactured lattice structure made by al... more In order to discuss the quality assurance of additively manufactured lattice structure made by aluminum alloy (AlSi10Mg) using 3D printing technology or selective laser sintering technique, compression test, micro-CT imaging and finite element analysis were carried out. The specimens were manufactured by 2 printing service companies with different expertise, which led to the choice of different process parameters such as the building direction, support structure, powder bed temperature and laser scanning speed. The largely scattered compressive peak loads were in good linear positive correlation with the weight, which is the easiest and convenient index for the quality assurance. On the other hand, the apparent density was almost the same. The reason why the weight of the products was largely scattered was investigated by micro-CT image analysis and finite element analysis. Also by comparison with the CAD data, the influence of manufacturer-dependent process parameters on the strength was discussed.
Journal of the Japan Society for Technology of Plasticity
An experimental procedure for the hot compression test for Ni-based alloy was proposed and evalua... more An experimental procedure for the hot compression test for Ni-based alloy was proposed and evaluated in order to obtain an appropriate stress-strain curve for numerical analysis. The effect of various parameters, i.e., top and bottom shapes of specimen, lubricant and jig/tool, on the deformation tendency was systematically studied. Ni-based alloy (CMSX-4), which has a higher strength than the specimen, was used as die for preventing temperature gradient. This improved the uniformity of temperature distribution in the specimen. The combination of a specimen having concentric circles on the end surface and a glass sheet as lubricant was the most appropriate to gain stable and low-friction condition of the specimen end. The proposed procedure of the hot compression test is applicable for the temperature range of 1173-1423 K and strain rate range of 0.01-5 s-1. The effectiveness of the obtained stress-strain curve was discussed from the viewpoint of the value and tendency of characteristic features observed in the flow stress curve. The maximum stress exhibited normal temperature and strain rate dependence. Related activation energy for deformation was similar in value to those in other reports.
Journal of the Japan Society for Technology of Plasticity, 2014