应用TAGUCHI法对微拉深成形有限元模拟结果的误差分析

ERROR ANALYSIS OF FINITE ELEMENT SIMULATING RESULTS OF MICRO DEEP DRAWING PROCESS BASED ON TAGUCHI METHOD

为考察基于传统本构模型和求解算法的有限元程序模拟金属微成形过程的适应性,设计正交试验,应用自行开发的板料成形有限元程序ARVIP-3D对微成形和等比放大10倍的常规成形进行模拟计算,并根据质量工程中的TAGUCHI法,参考信噪比的概念,对材料参数和工艺条件等因素对两类相似拉深的模拟结果误差进行了分析。结果表明:微成形中的尺度效应主要是成形机理与常规成形不同而引起的,基于传统本构模型和求解算法的有限元程序不能正确模拟微成形过程,但可以模拟出摩擦引起的尺度效应;宏微观尺度的成形模拟结果误差主要来自于浮点运算的误差,但几何和力学条件的处理也给模拟误差带来了影响。因此,在开发适合于微成形模拟的新型有限元程序中,不仅要考虑本构模型的特殊性,几何和力学条件的相关处理算法也应进行改进。

In order to investigate the applicability of finite element program based on the conventional constitutive model and the solving methods simulating the micro forming process, orthogonal experiments of the micro deep drawing and the corresponding conventional deep drawing zoomed in ten times are designed. A FEM-based program for sheet forming, ARVIP-3D, developed by our study team, is used to simulate these forming processes. TAGUCHI method and the concept of the signal-to-noise ratio are used to analyze the change ratio of the critical section thick influenced by the fluctuation or the deflection of the material performance parameters and the technology condition parameters. The results indicate that size effects on micro forming are principally induced by the different forming mechanism from macro forming, so the finite element program based on the conventional constitutive model and the solving methods can＇t accurately simulate the micro deep drawing process, but can simulate the micro size effects induced by friction; The error of the simulating results of these two similar deep drawing process principally root in the floating-point operation, but the fluctuations of the geometric and the mechanical conditions also affect the this kind of simulating error too. Accordingly, when the new-style finite elements program for micro forming is developed, not only the special constitutive models need to be established, but the processing algorithms of the geometric, contact and the mechanical conditions should also be improved.