A class of plastic constitutive equations with vertex effect. IV. Applications to prediction of forming limit strains of metal sheets under nonproportional loadings (Q1090496)

The simplified form of constitutive equation proposed by the author in part III of this series of papers [see the review above (Zbl 0621.73037)], is utilized to predict forming limit strains of metal sheets which are deformed along arbitrarily curved strain-paths without unloading, and deformed along straight strain path after another strain- path, with or without unloading at the strain-path change. The Stören- Rice localized bifurcation condition is used as the breakage condition [see \textit{S. Stören} and \textit{J. R. Rice}, J. Mech. Phys. Solids 23, 421-441 (1975; Zbl 0328.73029)]. A comparison of the theoretical and experimental curves is also presented. The existence of maximum and minimum forming limit diagrams is verified. The work presented by the author in the four papers of this series is interesting, and yields some very useful information on FLDs.