Plane strain finite element analysis of sheet forming operations including bending effects

An improved finite element method suitable for the plane-strain analysis of sheet metal forming operations is presented. The method incorporates a computationally efficient shell model and a consistent frictional contact algorithm through an implicit updated Lagrangian formulation. The workpiece material model is rigid-visco-plastic with a choice of power law hardening and plastic normal anisotropy, capable of modeling a wide variety of sheet metals. A simplified nonlinear incremental shell theory is employed along with an optional reduced integration through the thickness for computational efficiency, while retaining the advantages of the kinematic model containing the bending effects. Complex tool geometry can be handled by discrete data points, by primitives (lines and arcs), or by analytical functions.; The capabilities of the method are demonstrated through verification problems and comparisons with experimental data, benchmark results and published data for several practical problems of sheet metal forming industry. The problems include stretching and/or deep drawing operations, simulation of automobile panel section and brake bending operation.; As an independent investigation from the first portion of the dissertation, measured data from a set of simple bending experiments of two types of aluminum are presented and analyzed. Generated data from the experiments include strain histories (loading and unloading), springback information (springback angle and strains), and friction coefficients. As a by-product, a simple way of estimating the friction coefficient (Coulomb's law) during a bending operation is proposed and demonstrated.