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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. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

This investigation deals with the numerical and experimental study on the free vibration of woven glass fibre laminated composite stiffened plates. Thirty-four stiffened plates fabricated from woven glass fibre and binder (epoxy and hardener) by varying the parameters, such as numbers, types and orientation of stiffeners; depth of stiffener to thickness of plate ratio; and aspect ratio and boundary conditions of plates; are tested in FFT analyser to obtain their natural frequencies. A finite element model is used for vibration of laminated composite stiffened plates for validation of the experimental results. The experimental and numerical results are compared, which shows a very good agreement between them. From this study, it is observed that the above-mentioned parameters significantly influence the fundamental frequency. Since, the experimental investigation on laminated composite stiffened plates is scanty; this study can be considered as a reference for the future work. [ABSTRACT FROM AUTHOR]