STUDY ON THE INFLUENCE LAWS OF MECHANICAL PROPERTIES ON STIFFNESS OF AUTOMOTIVE BODY PANELS

The criterion and research technique of auto body panels stiffness are introduced in this work, and the finite element models (FEM) of cylindrical shallow shell that could represent auto body panels are established. Simulations of forming, springback and stiffness on cylindrical shallow shell are carried out. The simulations show great accuracy with the experimental results. Extensive simulated results of the influence laws of material mechanical properties on stiffness are achieved, such as yield strength, strain-hardening exponent, Young's modulus, anisotropy parameter and strength coefficient. With comparison of the weight coefficient of material mechanical properties on stiffness, it can be concluded that the Yong's modulus, strain-hardening exponent and yield strength are key influencing factors of stiffness. With the analysis of distribution of the strain after cylindrical shallow shell forming, plastic deformation during the forming process resulting in work-hardening of the material is one of the main reasons for increasing stiffness.