A STUDY OF THE STRETCHING PROCESS OF STEEL-POLYMER-STEEL LAMINATE

An elasto-plastic finite-element formulation of boundary value problem s has been developed for the large deformation SPS laminate stretching process. A geometric stiffness matrix resulting from the rotation of the principal axes of the material is added to the governing equation, the resulting non-linear equilibrium equations being solved by the us e of an incremental method with an r-minimum technique. Some phenomena in the stretching process of SPS laminate are presented in this paper , including the distributions of stress, strain and strain-energy dens ity in the material, the deformed geometry and the variation of the pu nch load with displacement. In addition, the locations of initial yiel ding and fracture initiation in the material are predicted by the stra in-energy density criterion. Experimental tests were performed, the re sults of which have exhibited a good consistency with the numerical si mulation. The method proposed here has been shown to be quite powerful and reliable, and can be modified for solving problems related to oth er manufacturing processes.