Vibration and Stability of Initially Stressed Hybrid Composite Plates in Hygrothermal Environments

Vibration and stability of hybrid composite plates with arbitrary initial stresses in hygrothermal environments are investigated. The governing equations, including the effects of moisture-caused, thermal, and initial stresses, are established based on the variational energy method. The influence of temperature and moisture on material properties of the hybrid composite plates is considered. The initial stress is taken to be a combination of a uniaxial load and pure bending. Example of an initially and hygrothermally stressed hybrid laminated plate with simply supported edges is solved. Effects of the layer thickness ratio, fiber volume fraction, initial stresses, temperature, and moisture concentration on the natural frequency and buckling load of hybrid composite plates are studied.