Abstract: The moisture absorption model and wet viscoelasticity of glass fiber/flax fiber hybrid composite laminates were established. The wet diffusion characteristics of hybrid composite laminates are analyzed by the general mass diffusion model. The wet viscoelasticity of hybrid composite laminates is simulated by three element model. The model parameters are measured by the thermal mechanical dynamics analysis (DMTA). Based on the principle of relative wetting weight gain time equivalence, the complex stiffness of hybrid composite laminates under different moisture absorption is analyzed.It is found that the process of absorption moisture of hybrid composite laminates (GFFG) is non Fick at the early stage of absorption moisture, and the hybrid composite laminates (FGGF) satisfy the Fick′s law of wet diffusion. When M_t is at 0~0.037, the gradient of the storage flexural stiffness of the hybrid composite laminates is larger than that of the composite laminates, and the increase of the storage flexural stiffness tends to be slow after 100 Hz. The model established in this paper can reflect the laws observed experimentally.

Key words: hybrid composite laminates, wet diffusion, wet viscoelasticity, gain rate of absorption moisture-time equivalence principle, complex stiffness