A micromechanics-based constitutive model for linear viscoelastic particle-reinforced composites

In this paper, a novel micromechanics-based constitutive model is proposed for linear viscoelastic particle-reinforced composites based on a homogenization approach in the time domain. After decomposing the deformation into its volumetric and deviatoric parts, the long-term responses of the constituents are utilized to formulate the constitutive equations of the composites. The strain energy contributions of the constituents are computed from micromechanics principles to derive the effective constitutive model of the composites. Representative volume element models with various particle volume fractions are constructed to validate the constitutive model numerically. The effects of the particle volume fraction, strain rate, and elastic and viscous parameters on the effective viscoelastic behaviors of the composites and the creep performances are investigated. The results reveal that the proposed constitutive model can predict well the effective properties of linear viscoelastic particle-reinforced composites in the time domain. The experimental results are also employed to validate the proposed constitutive model in the frequency domain. The findings suggest that the constitutive model can also provide satisfactory predictions for the behaviors of the linear viscoelastic particle-reinforced composites in the frequency domain. After the constitutive model is validated, the composites, exhibiting full relaxation behaviors, are discussed.