Bending characteristics of thick multidirectional composite plates under hygrothermal environment

Effects of moisture and temperature on the bending characteristics of thick multidirectional fibrous composite plates are studied. A three-dimensional finite element analysis procedure is developed using twenty noded isoparametric quadratic brick elements. A typical multidirectional unit cell is assumed to consist of several unidirectional composite blocks. Transformation-based relationships are used to generate the stiffness properties of a multidirectional composite model. The FE analysis accounts for the hygrothermal strains and reduced elastic properties of multidirectional composites at an elevated moisture concentration and temperature. Deflections and stresses are evaluated for thick multidirectional composite plates under uniform and linearly varying through-the-thickness temperature and moisture content. Results reveal the effects of fiber directionality on deflection and stresses.