Hygrothermal effects on free vibration of delaminated woven fiber composite plates – Numerical and experimental results

The present study deals with numerical and experimental investigations on free vibration behavior of woven fiber Glass/Epoxy delaminated composite plates subjected to elevated temperatures and moistures. A composite plate model based on first order shear deformation theory (FSDT) with provision of mid plane square delamination is considered for free vibration of delaminated composite plates subjected to hygrothermal loading. An eight noded quadratic isoparametric element with five degrees of freedom per node is used in the formulation. A series of experiments is conducted to obtain natural frequencies of vibration for woven fiber Glass/Epoxy delaminated composite plates using B&K FFT analyzer with PULSE software, which agree reasonably well with the numerical values. Teflon film is embedded in the laminate, simulating the presence of delamination. The effects of temperature, moisture, delamination size and different boundary conditions on the natural frequencies of composite plates are investigated. The results indicate that the vibration behavior is greatly influenced by the delamination and hygrothermal parameters involved in the study.