CREEP-BEHAVIOR OF UNIDIRECTIONAL COMPOSITES

The creep behavior of the continuous fiber reinforced unidirectional c omposites due to the viscoelasticity of the resin matrix is investigat ed assuming that the constituent matrix obeys the nonlinear creep law and the fiber is the linear elastic materials. Utilizing a quasi three -dimensional finite element method, the macroscopic creep behavior of the composites with regular fiber packing is obtained, giving the orth otropic creep law for the composites. Then, the creep of the composite s with random fiber packing is estimated applying the random model pro posed by Kondo and Saito in which the neat matrix cylinders are embedd ed in the regular array composites. The theoretical predictions for th e creep behavior are compared with the experimental results.