Non-crimp fabric (NCF) preforms are an attractive alternative to traditional preimpregnatedtapes due to their low manufacturing cost and high efficiency. Theorientation of the fibers in each layer can be tailored, independent of the other layers,to optimize the required load carrying capacity in that particular direction, makingthem capable of improved performance. Stitches help to keep the fiber tows in theNCF fabric straight during handling; however, the stitches prevent the fibers fromreorienting easily to accommodate complex shapes without wrinkling.In order for NCF fabrics to be used to create complex geometric shapes, theirdraping behavior needs to be understood with respect to different fabric variables sothat the draping performance can be maximized. To date, the draping behavior ofNCF fabrics has been only sparsely investigated in contrast to the amount of researchreported on woven fabrics.This paper presents an investigation on the role of fabric architecture in theformability of NCF fabrics. This study is a subset of a broad study conducted underthe purview of a Department of Energy project funded to General Motors fordeveloping state of the art computational tools for integrated manufacturing andstructural performance prediction of carbon fiber composites. For modeling thedraping behavior, fabric characterization tests such as bending and bias-extensionevaluations were conducted for NCF fabrics with varying areal weights andconstruction. Taking advantage of ESI’s PAM-FORM material model, asymmetricshear behavior was included in conjunction with different membrane and bendingbehavior to model the draping behavior of these fabrics. For this study, the fabriccharacterization data was first used to calibrate the draping models in simple shear andbending tests. Later these models were validated against the deformation of thefabrics when they were formed using a truncated pyramid tool designed at the GeneralMotors Research Labs to assess the drapeability of the dry fabrics.
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