Impact resistance of composite laminate flat plates - A parametric sensitivity analysis approach

Sensitivity analysis is a tool employed in engineering problems to identify the influence of input parameters on the state variables such as displacement, stress, strain and temperature. In the case of composite laminates the impact resistance depends on a number of parameters, which have been extensively studied by a number of researchers. But the reported work has thus far fallen short of providing the critical analysis on the order of degree of influence of the considered variables on the impact resistance of the composite laminates. In this work we present a sensitivity analysis approach to ascertain the degree of influence of various mechanical and material parameters on the impact performance of the composite laminated plates. Here we show that based on the normalized sensitivity coefficients, one can determine the influence of each individual parameter and hence identify the parameters, which need to be considered more critically in design. The normalized sensitivity coefficients hence give a numerical indicator of the factors having more influence on the impact resistance of the composite. This approach enables one to limit the number of material and geometric properties usually considered in design to the most critical ones for improving the low velocity impact behavior of the composite laminates. Our results indicate that the low velocity impact resistance of fiber reinforced polymer composite plates depends more significantly on the thickness and the stacking sequence and the effect of the elastic moduli of the fibers and matrix has less effect than the strength of the fiber and matrix materials of the composite. Initial numerical model was selected from the literature and the results verified against the available numerical and experimental results. The results show quite a good agreement with the experimental results. The results indicate that the impact performance depends significantly on the thickness and the stacking sequence and the effect of the elastic moduli of the fibers and matrix has less effect than the strength of the materials. These results will help in the further study to improve the impact resistance of the composite laminates as the focus should be more on the parameters like thickness, stacking sequence and materials having higher strengths.