Abstract
The temperature-dependent creep of a class of composite systems is considered with the inclusion of the microstructure. The material system is regarded as a three-dimensional viscoelastic matrix which is reinforced with randomly oriented, short viscoelastic fiber-bundles. The nonlinear creep response of the composite matrix is modeled within the considered temperature range, using a modified form of the hereditary constitutive equation in linear viscoelasticity. The time-dependent behavior of the individual fiber-bundle is formulated as a combination of a viscoelastic matrix substance within the bundle and an ensemble of unidirectional, elastic fibers. The macroscopic behavior of the randomly oriented, fiber-composite is determined, with the inclusion of the microstructure, using the laminate analogy which assumes that the random fiber-composite may be treated as a laminated “quasi-isotropic” material. The presented approach is illustrated numerically for the case of the creep of SMC-R50 composite system within a temperature range of 28° to 76°C. The theoretical model is presented in a generalized manner and could be applicable to a large class of composite systems.
