A woven reinforcement forming simulation method. Influence of the shear stiffness

A simulation method is proposed for forming processes of fabrics used as reinforcements of composite materials. It uses specific finite elements made of woven material. The nodal interior loads are deduced from yarn tensile strain energy and woven cell shear energy. A picture frame shear test is presented. Optical measures permit to analyse the strains in yarns at microlevel for the different stages of the shear test. The influence of shearing in the formulation is studied on two forming simulations. It is shown that taking shear into account permits the appearance and the development of wrinkles when the locking angle is overcome.