Folding design of composite structures

The folding of woven composite sheets made of carbon fiber reinforced plastic (CFRP) is studied herein. Minimum fold radii of an initially flat laminates made of 94 gsm plain weave, and 200 gsm 2 × 2 twill are estimated using maximum strain and Tsai–Wu failure criteria, and also measured experimentally. Estimated results are compared to the experimental values, showing good agreement. Z-folding of an initially flat laminate (three-ply 0/45/0 plain weave) is studied by geometrically nonlinear finite element modeling. The sizing of the cutouts that are required for multiple folds is based on minimum bend radius of the material. The folded configuration and highly strained regions are identified.