Science and Education Publishing American Journal of Mechanical Engineering 2 3 2014 06 16 Parametric Instability of Woven Fiber Laminated Composite Plates in Adverse Hygrothermal Environment 70 81 EN M. K. Rath Department of Civil Engineering, IGIT, Sarang, Odisha (INDIA) M. K. Dash AJME2014234 10.12691/ajme-2-3-4 2014 05 20 2014 06 04 2014 06 16 The present paper deals with the parametric instability of woven fiber laminated composite plates subjected to in plane periodic loadings in hygrothermal environment. The effects of various parameters like increase in number of layers, aspect ratios, side-to thickness ratios, static load factors, ply-orientations, lamination angle 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 using Bolotin's approach. The effects of transverse shear deformation and rotary inertia are used to study the anti-symmetric angle-ply rectangular plates. The onset of instability occurs earlier and the width of dynamic instability regions increases with rise in temperature and moisture for different parameters.