Papers by Keyword: Surface Deflection

Abstract: In this paper, the mechanism of surface low defect in sheet metal stamping is studied. Firstly, we simulate the forming procedure of a stamping component by Finite Element Method (FEM) to observe the growth of surface low defect. And then, we establish an analytical model and deduce the critical stress for local buckling. Finally, we take advantage of the critical stress to detect local buckling areas in the component. The FE simulation result shows that during springback the non-uniform displacement in the thickness direction forms surface low. Moreover, the detected local buckling area agrees with the experimental surface low area. This indicates that the essence of surface low phenomenon is panel’s local buckling under the residual compressive stress during springback.

Abstract: The surface deflection is an important disadvantage issue in the automobile outer panels forming. It can be controlled effectively through forming process. It is difficult to study the surface deflection because of the complexity of automobile panels. In this paper, a model of cylinder shallow shell is founded, and the measured method and evaluated standard of surface deflection for drawing parts are presented. The influence law of process techniques on surface deflection such as binder force, draw-bead, local force, and shape of blank-hold surface is achieved, which give a basic reference for controlling surface deflection.

Abstract: The impact line is a remarkable disadvantage in the auto body panels forming. It is difficult to study because of the complexity shape of automotive panels. The finite element models of hyperboloid shallow shells that can represent automotive panels are established, and suitability of finite element analysis to induce the impact line of automotive panel is carried out. The experiment test method for determining impact line is presented also. The criterion and research technique of auto body panels impact line are introduced. The consistency of results of simulation and experiment shows that the numerical simulation on research of impact line is accurate and feasible. Finally, research works of simulation and experiment on controlling impact line measures are carried out: effects of blank holding force (BHF), sheet thickness and lubricating modes on the impact line are obtained.