铝合金矩形管拉弯成形过程的数值模拟

采用动力显式有限元程序Pam-Stamp2000对铝合金矩形管的一种拉弯成形过程进行了模拟,分析了模具最大作用力、管材截面畸变、成形件回弹的变化规律.模拟结果和文献给出的实验结果相当吻合,即模具最大作用力、管材截面畸变均随预拉力的增加而增加,而成形零件的回弹随预拉的增加而减小;相同预拉状况下,增加壁厚有利于减小截面畸变.此外,数值模拟给出了模具对管材作用力及管材夹持端轴向拉伸作用力随模具行程的变化规律,揭示了本文的拉弯实质上是一种非恒定轴向作用力(呈渐增趋势)的拉弯成形方式,这与本文的解析结果高度一致.

Numerical simulation of a stretch-bending process for extruded aluminum rectangular tubes

Numerical simulation of a stretch-bending process for extruded aluminum rectangular tube is carried out using dynamic-explicit finite element code Pam-Stamp2000. It is shown that the maximum die force and cross section distortion increase with increasing pre-stretching, while springback shows a decrease trend. Under the same pre-stretching level, local distortion of cross section decreases when the tube wall thickness increases. Numerical simulation result agrees well with that of experiments presented in literature. Furthermore, an analytic approach is performed to describe the die force and the axial tensile force at tube end with respect to the die displacement. Also the agreement between the analytic model and the numerical simulation is highly satisfactory.