A comparative study of implicit and explicit FEM for the wrinkling prediction in the hydroforming process

The recent application of tube hydroforming in the automotive industry demands finite element analysis, since it is rapidly being used as an effective tool for the evaluation and optimisation of the design of hydroforming dies and processes. In this paper, attention is paid to the comparison of an implicit and an explicit FEM widely used for the hydroforming process. The influences of time scaling and mass scaling, which have been commonly used in order to save computational time in the explicit method, are especially investigated. The comparisons focus on the predictability of wrinkling and stress with various scaling factors in the explicit method. Through verifications with experimental results, a useful guideline in determining the scaling factors is proposed.