Multi-Scale Modeling of Crash & Failure of Reinforced Plastics Parts with DIGIMAT to LS-DYNA interface

This paper deals with the prediction of the overall behavior of polymer matrix composites and structures, based on mean-field homogenization. We present the basis of the mean-field homogenization incremental formulation and illustrate the method through the analysis of the impact properties of fiber reinforced structures. The present formulation is part of the DIGIMAT [1] software, and its interface to LS-DYNA, enabling multi-scale FE analysis of theses composite structures. Impact tests on glass fiber reinforced plastic structures using DIGIMAT coupled to LS-DYNA allow to analyze the sensitivity of the impact properties to the polymer properties, fibers’ concentration, orientation, length ... For such impact applications the material models used for the polymer matrix are usually based on nonlinear elasto-viscoplastic laws. Failure criterion can also be defined in DIGIMAT at macroscopic and/or microscopic levels and can be used to predict the stiffness reduction prior to failure (i.e. by using the First Pseudo Grain Failure model). Theses failure criterion can be expressed in terms of stresses or strains and use strain rate dependent strengths. Finally, the interface to LS-DYNA, available for the MPP version, will be used to run such multi-scale FE simulations on Linux DMP clusters. The application will thus involve: LS-DYNA MPP to solve the structural problem. DIGIMAT-MF as the material modeler. DIGIMAT to LS-DYNA MPP strongly coupled interface to perform nonlinear multi-scale FEA DIGIMAT-MF composite material models based on : - An elasto-viscoplastic material model for the matrix, - An elastic material model for the fibers as well as the fiber volume content, fiber length and fiber orientation coming from an injection code, - Failure indicators computed at the microscopic level.