Vibration and Buckling of Composite Twisted Panels
Subjected to Hygrothermal Environment

Abstract

The twisted cantilever panels have significant applications in wide chord turbine blades, compressor blades, fan lades, aircraft or marine propellers, helicopter blades, and particularly in gas turbines . These structural members are often subjected to various environmental loads during their service life. The presence of temperature and moisture concentration may significantly reduce the stiffness and strength of the structures and may affect some design parameter such as vibration and stability characteristics of the structures. To avoid the typical problems caused by vibrations and stability, it is important to determine natural frequency, critical buckling load of the composite laminated pre twisted cantilever panels under hygrothermal conditions. Therefore the vibration and buckling behavior of laminated composite twist ed panels subjected to hygrothermal loadings are studied in the present investigation.
The present study deals with the free vibration and buckling analysis of pre- twisted cantilever laminated composite panels subjected to hygrothermal loading using Finite element method. A computer program based on FEM in MATLAB environment is developed to perform all necessary computations. Here eight noded isoparametric quadratic shell element with five degrees of freedom per node is used based on FSDT theory with hygrothermal loading. The influences of various parameters such as angle of twist, aspect ratio and lamination parameters are examined on the vibration and buckling characteristics of laminated twisted
panels subjected to hygrothermal loads. Numerical results a re presented to show the effects of pre- twist angles, geometry and lamination details on the vibration and buckling characteristics of twisted plates.