Viscoelastic lattice spring model for mechanical behavior of polymeric particle filled composites

In this work, viscoelasticity has been introduced into lattice spring model by utilizing van der Pol elements obeying the Boltzmann superposition principle to investigate the time-dependent mechanical behavior and damage evolution of viscoelastic particle filled composites (PFCs). Stress relaxation, crack mouth opening displacement test and uniaxial tension were simulated. Influence of filler content, filler dispersion state, strain rate and interfacial strength on the tensile response of PFCs were investigated. It is shown that (1) viscoelasticity of microscopic elements can be reflected to the global behavior of composites; (2) cluster effects exists when particles are closely packed and it will cause incipient damage under low extent of deformation; (3) increase in strain rate strengthens both the stiffness and strength of composites and the increment is proportional to the logarithm of strain rate; (4) well-dispersed PFCs can be severely weakened when adequate interfacial bonding is not provided.