Compressive Splitting Failure in Fiber Reinforced Unidirectional Composites Using Modified Shear Lag Theory

Compressive failure by splitting is studied herein via an analytical model. The use of a shear lag model to determine the stress state at the crack tip and the modeling of the region away from the crack tip by the 3D elasticity equations leads to a simple analytical expression is used to determine the compliance changes for both unsteady crack growth as well as steady state crack growth under compressive loading. Certain modifications to the assumptions used in the classical shear lag model have been made to increase the accuracy of the predictions for the rate of change of compliance with respect to crack length, ^. The present approach leads to closed form expressions for the compressive strength of unidirectional fiber reinforced composites.