A modular cantilever fixture and test methodology for thermoplastics: An alternative bending load case for validation of CAE material models

Abstract

Several conventional CAE material models account for only uniaxial tensile behavior of the material; however, the said models may be required to predict component-level response in a complex loading scenario. Therefore in developing input files for such models, it becomes critical to evaluate their performance in alternative validation loading scenarios such as 3-point bending (flexure). Simulating 3-point flexure requires optimization of contact parameters, thereby introducing an extraneous factor that adds uncertainty to the validation of the material model in bending scenarios.This paper targets to evaluate the opportunity to substitute the conventional 3-point flexure with a cantilever bending exercise as the method of choice for bending load case validation. The cantilever bending test is expected to alleviate several challenges associated with CAE validation using 3-point flexure. We describe a novel test fixture for carrying out cantilever bending at low velocities; the fixture can be conveniently mounted on commercial Universal Testing Machines (UTM), and is capable of generating precise load–displacement information. Cantilever and flexure simulations in LS-DYNA employing piecewise-linear-plasticity formulation (*MAT_024) highlight the relative simplicity of validation in bending using cantilever loading. Further, the equivalence of the bending kinematics during cantilever and 3-point flexure is assessed through investigation of stress–strain information.