一种Ti6Al4V的本构参数模型及其有限元仿真研究

摘要

利用SHPB实验研究得到了Ti6Al4V在高应变率条件下的应力－应变关系，拟合出了一种Ti6Al4V的J⁃C本构方程的新的参数模型。在此基础上，基于ABAQUS软件的Explicit分析，建立了Ti6Al4V高速铣削的二维简化模型并进行了仿真研究。仿真结果表明：热塑性失稳和塑性侧滑是引起锯齿形切屑的主要原因；锯齿化程度Gs 随着铣削速度的增加而降低，随着进给速度的增加而增加，揭示了锯齿形切屑的形成过程并对高速铣削Ti6Al4V的加工参数选择提供了参考。进行了实际的高速铣削实验，实验表明：仿真所得切屑形状与实验所得切屑形状吻合度较高。%By SHPB ( Split Hopkinson Pressure Bar) test study conducted, the relation of stress⁃stress change of Ti6Al4V under condition of high stress change rate was obtained to fit out a new J⁃C constitutive equation parameters model of Ti6Al4V. Based on this, a simplified two⁃dimensional (2⁃D) model for high⁃speed milling Ti6Al4V based on ABAQUS/Explicit software analysis was estab⁃lished, and studied with simulation. The simulation results show that thermoplastic instability and plastic side flow is the main cause for saw tooth chip. The chip saw⁃tooth degree Gs decreases when increasing rotating speed, while it increases when increasing feed speed. Useful understanding of the forming process of saw⁃tooth chip is made, which provides reference for selection of machining parameters of high⁃speed milling Ti6Al4V. Actual high⁃speed milling experiments were carried out. Experiments show that chip shape of the simu⁃lation and experimental results agree well.