为研究一种高强钢的静动态力学特性并构建Johnson-Cook本构模型,利用电子万能试验机进行了准静态压缩和拉伸试验,获取了材料在室温准静态条件下的应力-应变曲线、弹性模量和泊松比。通过分离式霍普金森压杆,在293~1073 K 5种温度和800~2...为研究一种高强钢的静动态力学特性并构建Johnson-Cook本构模型,利用电子万能试验机进行了准静态压缩和拉伸试验,获取了材料在室温准静态条件下的应力-应变曲线、弹性模量和泊松比。通过分离式霍普金森压杆,在293~1073 K 5种温度和800~2100 s^(-1)4种应变率下开展动态压缩试验,获得了材料在不同条件下的动态应力-应变曲线。最后,基于试验数据构建其Johnson-Cook本构模型,并对模型的准确性进行验证。结果表明:材料的屈服应力随着应变率的增加而增加,但增长幅度较小,应变率强化效应不显著;当应变率为1000 s^(-1)时,材料的屈服应力随温度升高而显著降低。通过本构模型计算得到的应力-应变曲线与试验结果吻合良好,表明模型能够较准确地预测材料的应力行为。展开更多
Numerical control（NC） warm bending is a proven strategy to form the large diameter thin-walled（LDTW） Ti-6 Al-4 V tubes, which are typical light-weight and high-performance structural components urgently required i...Numerical control（NC） warm bending is a proven strategy to form the large diameter thin-walled（LDTW） Ti-6 Al-4 V tubes, which are typical light-weight and high-performance structural components urgently required in many industries. In virtue of unveiling the thermo-mechanical coupled deformation behaviors, uniaxial tensile tests were conducted on Ti-6 Al-4 V tube within wide ranges of temperatures（25-600 ℃） and strain rates（0.00067-0.1 s～（-1））. Moreover, a modified Johnson-Cook（JC） model is proposed with a consideration of nonlinear strain rate hardening and the interaction between strain hardening and thermal softening. Resultantly, the present model gives more accurate predictions for flow stress over the entire deformation ranges and the maximum error decreases by about 90%. By employing proposed model to NC warm bending, preferable precision is obtained in predicting forming defects including fracture, wrinkling and over thinning. The present work lays foundation for the forming limit prediction and process optimization in NC warm bending of LDTW Ti-6 Al-4 V tubes.展开更多
文摘为研究一种高强钢的静动态力学特性并构建Johnson-Cook本构模型,利用电子万能试验机进行了准静态压缩和拉伸试验,获取了材料在室温准静态条件下的应力-应变曲线、弹性模量和泊松比。通过分离式霍普金森压杆,在293~1073 K 5种温度和800~2100 s^(-1)4种应变率下开展动态压缩试验,获得了材料在不同条件下的动态应力-应变曲线。最后,基于试验数据构建其Johnson-Cook本构模型,并对模型的准确性进行验证。结果表明:材料的屈服应力随着应变率的增加而增加,但增长幅度较小,应变率强化效应不显著;当应变率为1000 s^(-1)时,材料的屈服应力随温度升高而显著降低。通过本构模型计算得到的应力-应变曲线与试验结果吻合良好,表明模型能够较准确地预测材料的应力行为。
基金Projects(50905144,51275415)supported by the National Natural Science Foundation of ChinaProject supported by the Program for New Century Excellent Talents in University,China+1 种基金Project(3102014KYJD001)supported by Fundamental Research Funds for the Central Universities,ChinaProject(B08040)supported by Program of Introducing Talents of Discipline to Universities("111"Project),China
文摘Numerical control（NC） warm bending is a proven strategy to form the large diameter thin-walled（LDTW） Ti-6 Al-4 V tubes, which are typical light-weight and high-performance structural components urgently required in many industries. In virtue of unveiling the thermo-mechanical coupled deformation behaviors, uniaxial tensile tests were conducted on Ti-6 Al-4 V tube within wide ranges of temperatures（25-600 ℃） and strain rates（0.00067-0.1 s～（-1））. Moreover, a modified Johnson-Cook（JC） model is proposed with a consideration of nonlinear strain rate hardening and the interaction between strain hardening and thermal softening. Resultantly, the present model gives more accurate predictions for flow stress over the entire deformation ranges and the maximum error decreases by about 90%. By employing proposed model to NC warm bending, preferable precision is obtained in predicting forming defects including fracture, wrinkling and over thinning. The present work lays foundation for the forming limit prediction and process optimization in NC warm bending of LDTW Ti-6 Al-4 V tubes.
