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Hygrothermal effects on free vibration of woven fiber glass/epoxy laminated composite cylindrical shallow shells are investigated both numerically and experimentally. In the present finite element analysis a composite doubly curved shell model based on first order shear deformation theory (FSDT) is used for free vibration of cylindrical shell panels in hygrothermal environment. B&K FFT analyzer is used to determine the natural frequencies of vibration experimentally by conducting non-destructive testing. The effects of curvature ratios, lamination sequences and boundary conditions on natural frequencies of vibration under hygrothermal loading are investigated. The frequency of vibration decreases with increase of temperature and moisture. [ABSTRACT FROM AUTHOR]

The present study deals with the finite element analysis of parametric instability characteristics of delaminated bidirectional Glass/Epoxy composite panels exposed to hygrothermal field with harmonic in-plane loading based on first order shear deformation theory. An 8-noded isoparametric finite element model was developed which takes account of the influences of area delamination and hygrothermal environment for predicting dynamic instability regions of composite flat panels. Validation of numerical results from finite element analysis was done with those available from previous researches. The influences of various parameters like static load factor, area of delamination, temperature, moisture, fiber orientations, boundary conditions and stacking sequence on the dynamic instability regions of bidirectional Glass/Epoxy flat panels were investigated. Significant effects of these parameters on the dynamic stability characteristics of composite plates were observed and discussed. [ABSTRACT FROM AUTHOR]