A modular modeling approach for describing the in-plane forming behavior of unidirectional non-crimp-fabrics

Abstract

Various commercially available unidirectional (UD) non-crimp-fabrics (NCFs) are currently used for manufacturing carbon fiber reinforced plastic (CFRP) parts. These UD NCFs can differ significantly in their forming behavior. For optimizing and ensuring the manufacturability of the forming process of CFRP parts manufactured from UD NCFs these differences have to be taken into account. This motivates developing an efficient and universally applicable modular modeling approach for describing the in-plane forming behavior of various UD NCFs. The first component of this modular approach is a hyperelastic material model that accurately predicts the fiber orientation of UD NCFs during forming. This material model is implemented via a user-defined material subroutine in the commercial finite element package LS-DYNA. The second component is a simple truss structure that allows modeling the various stitch patterns of the different UD NCFs. This modular model can be calibrated via simple tensile tests. To demonstrate the versatility of this approach, the in-plane forming behavior of three different UD NCFs is validated by comparing experimental data and simulation results of the common picture frame test.