车身覆盖件冲压成形面畸变缺陷形成机理研究

Mechanism of Surface Low during the Stamping Process of Automobile Exterior Panels

面畸变是汽车外板冲压成形中一种常见的零件表面缺陷,对整车的外观质量有很大的影响。以车门外板为原型设计车门把手特征件,分别用探针式表面轮廓扫描仪与油石打磨的方法对零件面畸变缺陷进行检测与扫描,从而确定零件面畸变的分布情况。采用有限元仿真的方法对典型面畸变零件的局部变形特点和残余应力分布进行分析,进而对不同面畸变缺陷形成的力学机理分别进行分析。研究结果表明,局部拉弯变形不充分、弯曲与反弯曲效应、平面拉压作用下的局部屈曲共同构成了面畸变缺陷的形成机理。研究结果揭示了面畸变缺陷形成机理的多样性,为解决汽车外板的面畸变问题提供理论依据。

Surface low is one kind of the surface defects in automobile exterior stamping panels. It has a great influence on the cosmetic appearance of automobile. A door handle part according to the character of the automobile door exterior panel is designed. In order to determine the distribution of surface deflections, the part is grinded with oil stone and measure the contour curves by a stylus instrument, respectively. Finite element simulations of representative surface deflection parts are conducted to observe the local deformation and the distribution of residual stress in surface deflection areas. The mechanism of various surface deflections is explained, respectively. The research indicates that insufficient bending and stretching, the effect of bending and unbending effect and the local buckling under compressive stress are the mechanism of surface deflections. The work reveals the diversity of the mechanism of surface deflections and provides the theoretical evidence for quality control of surface deflections in automobile exterior panels.