Investigation of *MAT_58 for Modeling Braided Composites

An in-depth analysis is needed to simulate the impact behavior of triaxially braided composite materials. Before an impact simulation can be generated, all material input parameters must be found. The objective of this work is to use static tests conducted on axial and transverse coupons to determine these input parameters. In particular, analysis methods that capture the architecturally dependent damage observed in these tests in a computationally efficient manner are required. A macromechanical shell element based model for braided composites has been developed, in which the braid architecture is approximated as a series of four parallel laminated composites with varying fiber orientations. The composite damage model *MAT_58, available within LS- DYNA®, is used in this investigation. Careful investigation of the model’s global response, and local stress and strain distribution within each element of the composite unit cell are examined parametrically using various input strength parameters. From these studies, relatively small changes in the input parameters have been found to have a significant effect on the overall response, sometimes in non-intuitive ways. Thru this investigation the predictive capability of the developed braid model will be improved and a greater understanding of the functionality of the MAT_58 material model will be obtained.