Deep-drawing simulation of knitted fabric reinforced thermoplastics by homogenization theory and experimental verification

A novel computational method for deep-drawing simulation of composite materials has been proposed with taking a three-dimensional continuum mechanics approach. The most notable feature is the consideration of micro-macro coupling effects by the mathematical homogenization theory. The homogenized properties and the constitutive law are evaluated carefully using the three-dimensional microstructure model under the large deformation and biaxial loading conditions. In this paper, the knit reinforcement of aramid fiber is studied, which has very complex microstructure architecture. The polypropylene is used as the matrix. The newly developed deep-drawing simulation provides us the macroscopic deformation, strain, stress and stiffness distribution as well as the largely deformed microstructures in the deep-drawn product. The high-speed computing technique which has been developed in the previous report enables us to carry out the micro-macro coupled nonlinear analysis easily on the personal computer. The experimental work has also been conducted, and the largely deformed microstructures are compared between experiment and simulation. A good coincident was obtained, which implies the validity and reliability of the proposed computational method.