Effect of viscoelasticity on interfacial stress transfer mechanism in biocomposites: A theoretical study of viscoelastic shear lag model

Abstract

Biocomposite with regularly staggered alignment microstructure is frequently observed in natural biological tissues, and exhibits superior mechanical behavior. Owing to their viscoelastic nature, biocomposites exhibit stress rate-dependent stiffness function and mechanical behavior. In this paper, a linear viscoelastic shear lag model (SLM) is proposed to illustrate the micromechanical behavior of biocomposites under triangular loading pulse. Theoretical and numerical results are derived to predict the deformation and stress transfer between fibers and interfibrous matrix while the biocomposite is transiently stretched. The results from the analytical and numerical solutions demonstrate that how the fiber overlap length and loading rate affect the stress transfer and mechanical properties of biocomposites. The structure-property correlation is illustrated for viscoelastic biomaterials under transient loading, and existence of characteristic length of soft matter with viscoelastic property is involved in load transfer mechanism between the adjacent reinforcements in transient regime, which optimizes the load transfer mechanism between the adjacent reinforcements. Furthermore, we found that discontinuous fibril model could ensure large relative sliding deformation, helping dissipate energy, protecting fibril from overall damage, and achieving high ductility and high toughness, which can provide beneficial design strategies for engineering fiber reinforced composites.