(1. 西安石油大学 材料科学与工程学院,西安 710065;
2. 西北工业大学 凝固技术国家重点实验室,西安 710072)
摘 要: 基于环形试样轴压实验、有限元模拟、回归分析和遗传算法相结合的反求方法对厚壁钛管压缩状态下的塑性材料参数进行快速识别,利用试验方法研究机床弹性变形时TA18厚壁钛管不同圆环压缩试样高度下试样鼓肚率和机床弹性变形的变化情况,并在此基础上确定了试样高度范围,获得了试验力-位移曲线。利用反求方法确定了其压缩应力应变关系,并将其应用在不同高度钛管环形试样轴压模拟中,与试验进行对比,以发现反求获得的应力-应变曲线可以较好地预测钛管轴向压缩变形行为,对压缩试样变形后最大直径和载荷的预测误差分别不超过1.5%和11%。
关键字: 厚壁钛管;圆环压缩试样;反求方法;压缩应力状态;应力-应变关系
(1. School of Materials Science and Engineering, Xi’an Shiyou University, Xi’an 710065, China;
2. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China)
Abstract:An inverse method for fast and accurate identifying the material parameters of thick-walled titanium alloy tube under compressive stress state was developed combing ring axial compression test, FE method, regression analysis and genetic algorithm. Considering the evitable elastic deformation of testing machine, the specimen barreling and machine elastic deformation were examined in testing thick-walled TA18 tube specimen with varying heights. Then, a reasonable range of specimen height and the experimental load-displacement curves were determined accordingly. Employing the curves, the material parameters of tube were obtained by using the inverse method. In order to verify the reliability of the identified parameters, FE simulations of ring compression tests were carried out using the determined material parameters and compared with experiments. Comparison results show that the obtained stress-strain curves can describe the compressive deformation behaviors of tube material with prediction errors of maximum diameter, and the load deviates from the experiments less than 1.5% and 11%, respectively.
Key words: thick-walled titanium alloy tube; ring compression specimen; reverse method; compressive stress state; stress-strain relationship