An Experimental Investigation on the Effect of 3-D Stresses at Free Edges on the Failure of Composite Laminates under Distributed Lateral Load

Rapid increase in interlaminar and normal stresses of composite laminates with different lamina fiber directions at their free edges is known as “Free Edge Effect”. Normally three dimensional elasticity solution methods are required to analyze such plates. Kantrovitch method is one of these analytical techniques. In this method displacement field is initially assumed to be a sum of multiplication of single variable functions and then the differential equations are solved in one of the unknowns coordinate direction. The results from this solution are then implemented for next step to find known functions for other directions. The process will repeat until getting convergency. In this paper the basic concepts of the required theory are firstly introduced. The problem is then solved and results are verified with those available in the literature works. In the second main part of the paper, a test setup is introduced which is used to test various composite laminates to validate the theory results for failure prediction. Comparing failure load results are shown that there is a good agreement between the results from the analytical and experimental methods.