Novel Multi-scale Modeling of Woven Fabric Composites for use in Impact Studies

A novel approach to the multi scale modeling of the impact of woven fabrics using LS-DYNA® has been presented. This new technique entitled ‘Hybrid Element Analysis (HEA)’ incorporates the use of different finite elements at both a single and multiple level of modeling. A yarn level resolution is maintained around the impact zone or local region, while a homogenized resolution has been used for the far field or global region. The central patch of yarn level resolution uses a combination of solid and shell elements. A new method for modeling individual yarns using shell elements is discussed, which more accurately captures the geometrical contours of the yarn cross section. The surrounding homogenized zone uses shell elements. Interfaces using various types of tie-constraints are created between the different finite elements at the various scales of modeling. The acoustic impedances have been matched across the interfaces. A systematic approach is presented to determine the geometric and material parameters of the homogenized zone. The HEA approach maintains the accuracy of using a fabric model comprised entirely with yarn level resolution utilizing solid elements, but at a fraction of the computational expense. This enables the finite element simulation of multi layered fabric systems with very large domains, which was previously very difficult because of the impractical computational requirements of such an exceedingly large model. Compared to previous numerical multi-scale models, the finite element model using the HEA approach presented in this paper more accurately captures the entire impact event at a lower computational expense, making it a very useful tool for future studies.