Investigation of wrinkling failure mechanics in metal spinning by Box-Behnken design of experiments using finite element method

An investigation into material wrinkling failure mechanics of conventional metal spinning and the effects of process parameters and material properties are presented in this paper. By developing finite element (FE) models using the Box-Behnken design of experiments, the effects of six key process and material parameters on the start of material wrinkling have been investigated. These key factors include roller feed per pass, feed rate, blank thickness, tool path profile, material Young’s modulus, yield stress and strain hardening exponent. The results of FE simulation are validated by comparing the modelled roller tool forces and spun part end shape with those measured during a spinning experiment. From FE simulations, large residual stresses in the form of bending moments are found to be present in the flange of the blank, induced by the roller contact. It is found that material wrinkling failure begins when a plastic hinge is formed between the roller and the edge of the blank. It is found that both roller feed per pass and feed rate produce the most significant effect on the initiation of wrinkling failure, as they increase the bending stresses causing a plastic hinge to form more rapidly, thus wrinkling to occur more quickly.