The objective of this research is to understand the progressive damage that occurs in composite materials beyond their peak response and the interaction of multiple failure modes. Bi-axial bending is a test method that utilizes a Teflon Insert to explore damage propagation and interaction throughout the test. This work builds upon previous testing methods performed by McElroy and moves on to more traditional stacking sequences [1]. A model is created to explore damage interactions within a square plate. The square plate is loaded on edge, where a Teflon insert is located at the mid plane of the composite.This causes damage initiation and propagation to begin at the midplane and at the Teflon insert. As of now, modeling has been pursued to validate the thought that this experiment will allow the isolation and control of damage. To attempt to validate the experiments using a finite element code, a weak cohesive zone was applied to imitate the Teflon insert and act as a stress concentration. Another method where a Teflon insert is explicitly modeled with different properties at the midplane of the composite showed better results of isolation and damage control. This modeling and testing effort utilizing NDE and high-fidelity modeling will provide a better understanding of polymer matrix composite damage interaction.
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