Contact problems are intrinsic and indispensable in materials forming. They are divided into two categories, one the contact between the dies or molds and the workpiece and the other the self-contact between deforming workpiece free surfaces. Many research works were carried out for the study of the contact between the dies and the workpiece compared to the other because of complexity of the problem.
In this study, a new contact algorithm for the finite element analysis of free surface contact problem in materials forming is presented. The proposed contact algorithm consists of two parts: the first is the contact searching part and the second the constraint part. The contact searching algorithm does not require any a priori knowledge of the pairs of contact nodes or segments. G method and a variant of penalty function scheme were proposed for satisfying the impenetrability constraint in the present investigation.
Void closure in open-die forging and compression molding of SMC (Sheet Molding Compound) were simulated to verify the accuracy and capability of the currently developed contact algorithm. The simulation results were compared well to the experimental data available in the literature and the numerical results from ABAQUS.