Different approaches for the simulation of wrinkling during forming of textile reinforcements are presented. It is shown that 3D finite element modeling requires the consideration of an additional bending stiffness of the fibers. In shell-type modeling, the bending stiffness is important because it conditions the size of the wrinkles. Different methods to take into account the bending stiffness independently of the tensile stiffness are presented. The onset and development of wrinkles during forming is a global problem that concerns all deformation modes. It is shown in examples that the shear locking angle is not sufficient to conclude about the development of wrinkles. This article highlights the two points common to the different cases of wrinkling of continuous fiber textile reinforcements: the quasi-inextensibility of the fibers and the possible slippage between the fibers. It presents and compares different approaches to consider these two aspects. The simulation of the simultaneous forming of multilayered textile reinforcements makes it possible to see the influence of the orientation of different plies which is an important factor with regard to wrinkling.

When a thick laminate is subjected to bending, under certain boundary conditions, wrinkles may appear and develop due to the inextensibility of the fibers. Wrinkling is one of the most critical defects in composite manufacturing. Numerical simulation of the onset and growth of such wrinkles is an important tool for defining optimal process parameters. Herein, several bending experiments of thick laminates are presented. They were found to lead to severe wrinkling and delamination of different kinds. It is shown that the history of loading changed the developed wrinkles. Stress resultant shell finite elements specific to textile reinforcement forming show their relevance to provide, for these wrinkles induced by bending, results in good agreement with the experiments, both with regard to the onset of the wrinkles and to their development. This numerical approach was used to improve the understanding of the phenomena involved in wrinkling and to define the conditions required to avoid it in a given process.

ESAFORM is an association with the mission to stimulate applied and fundamental research in the field of material forming. Its annual conference, the International ESAFORM Conference on Material Forming, is used to achieve one of the main goals of ESAFORM: to spread scientific and technological information related to material forming within academic and industry. The next conference will be held online on 14-16 April 2021.