Experimental and numerical studies on free vibration of laminated composite shallow shells in hygrothermal environment

The present study deals with numerical and experimental investigations on free vibration behavior of woven fiber Glass/Epoxy laminated composite shells subjected to hygrothermal environments. A composite doubly curved shell model based on first order shear deformation theory (FSDT) is considered for free vibration of shells subjected to elevated temperatures and moisture concentrations. A quadratic eight-noded isoparametric element is used for the analysis. Series of experiments is conducted to obtain natural frequencies of vibration for woven fiber Glass/Epoxy laminated composite shells using B&K FFT analyzer with PULSE software. Parametric study is carried out varying the curvature ratios, number of layers of laminate and lamination sequences on fundamental natural frequencies of laminated composite shells for different temperature and moisture concentration under different boundary conditions. The numerical and experimental results show that there is a reduction in natural frequency of laminated composite shells with the increase in temperature and moisture concentrations.