Finite Element Modeling of Co-Mingled Glass/Thermoplastic Fabrics for Low-Cost/High-Volume Composites Manufacturing

The stamping of co-mingled glass/thermoplastic textiles for manufacturing relatively low- cost/high-volume structural composite automotive parts, e.g. truck beds and floor pans, is extremely attractive. These textile materials have yarns comprised of polymer fibers interwoven with the structural fibers, e.g. fiberglass. By heating the textiles in an oven, the polymer fibers melt and infuse the yarn, thereby removing the need to apply the resin in a separate step. The heated fabric can subsequently be stamped into a structural shape. The difficulty these fabric materials exhibit is that their deformation response exhibits both geometrical and materially nonlinear behaviors. The candidate material being evaluated in this study has a weave structure. The stamping mold for the current research is a hemispherical shape. Several samples of the candidate material were stamped to a variety of depths and over a range of temperatures to see how the sides of the material draw in as the part is being stamped. Splits on the hemispherical portion and wrinkles on the adjacent flat surface were observed. Several material models inherent to LS-DYNA were evaluated and a user-supplied subroutine was incorporated to consider the weave architecture. The correlation of the experimental and finite element results are presented.