A Novel Anisotropic Hyper-viscoelastic Model for Predicting Fabric Draping Responses

Abstract

In Liquid Composite Molding (LCM), fabric draping determines the local fiber orientation which significantly affects the fabric permeability in the subsequent resin infusion and curing processes. This study aims to predict the deformation of multi-ply textile woven fabrics and the punch force during the fabric draping process through a hyper-viscoelastic constitutive modeling approach. Each ply of fabric is treated as a homogeneous anisotropic solid whose strain energy density function is developed based on a unit woven cell. The proposed constitutive model integrates fabric relaxation responses which have been clearly observed in the experiment. A generalized Maxwell model is used to simulate the evolution of nonequilibrium stresses generated during in-plane shear, transverse shear, and through-thickness compaction deformation. The proposed novel constitutive model was implemented in the commercial Finite Element Analysis (FEA) software Abaqus as a user-defined material subroutine, UMAT. Experiments including picture frame shear, cantilever beam bending, and through-thickness compaction tests were carried out to characterize the material properties of a sheet of fabric. The modeling approach was applied to simulate the fabric deformation response during a hemisphere draping process to demonstrate the predictive capability.