Abstract
The present paper investigates the parametric instability of square laminated plates subjected to periodic dynamic loadings in hygrothermal environment. The effects of various parameters like the increase in static load factor and the degree of orthotropy of simply supported composite plates at elevated temperatures and moisture concentrations on the principal instability regions are investigated using finite element method. The effects of transverse shear deformation and rotary inertia are used to study the antisymmetric angle-ply square plates. A simple laminated plate model is developed for the parametric instability of square laminated plates subjected to hygrothermal loading. A computer program based on FEM in MATLAB environment is developed to perform all necessary computations. The results show that instability of square laminated plates occurs for different parameters with an increase in temperature and moisture environment. The onset of instability occurs earlier, and the width of dynamic instability regions increases with a rise in temperature and moisture for different parameters. The effect of damping shows that there is a finite critical value of dynamic load factor for each instability region below which the square laminated plates cannot become unstable.
Highlights
There is a tremendous increase in the utilization of composite materials in thin-walled structural components of high speed aircrafts, submarines, automobiles and other high-performance application areas
The principal instability regions of woven fiber laminated composite plates subjected to in-plane periodic loads are plotted with non-dimensional frequency Ω/ω versus the dynamic in-plane load β
The variations of dynamic instability regions with increase in static in-plane loads of woven fiber composite plates with increase in moisture concentrations of 0.25%, 0.5%, and 1% are observed as shown in Figures 6, 7, and 8 respectively
Summary
There is a tremendous increase in the utilization of composite materials in thin-walled structural components of high speed aircrafts, submarines, automobiles and other high-performance application areas. Sai Ram and Sinha [2] investigated the effects of moisture and temperature on the free vibration of laminated composite plates using finite element method. Ram and Sinha [5] investigated the effects of moisture and temperature on the static stability of laminated composite plates. Few studies are available on the behavior of composite plates under ambient temperature and moisture subjected to in-plane loads. Patel et al [11] investigated the dynamic instability of laminated composite plates supported on elastic foundations and subjected to periodic in-plane loads, using C1 eight-nodded shear-flexible plate element. Sahu and Datta [12] presented the dynamic stability behavior of laminated composite curved panels subjected to in-plane static and periodic compressive loads using finite element method. The boundaries of instability region were obtained using Bolotin’s method and were represented in amplitude-excitation frequency plane
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