Experimental and Numerical Investigation on Effect of Cut-Outs on Modal Parameters of FRP Composite Plates

Modal analysis of a quasi-isotropic Fiber Reinforced Polymer (FRP) composite plates having different cut-outs is numerically investigated under free-clamped boundary conditions using ANSYS 2023 R1. First six natural frequencies & corresponding mode shapes are extracted from the simulation. To verify the numerical results, experimental modal analysis is carried out on a sample specimen made of epoxy/glass composite with traditional ‘strike method ‘to determine the frequency response functions and to measure the natural frequencies. Investigation was continued to understand the effect of fiber orientation and systematically altered length to breadth ratio (size ratio - a/b) on the natural frequencies and the respective mode shapes. Obtained results exhibited that the correctly chosen fiber orientation contributes to improved dynamic performance, which delivers greater flexibility in designing structures to meet the application requirements. Furthermore, optimization of cut-outs was performed to demonstrate that variation in cut-outs is a key parameter and can be used to attain essential vibration mode shapes and definite frequencies. It was found from the investigation that circular cut-out acts a vital role for attaining desired free modal characteristics.