Time-dependent behavior of discontinuous biocomposites in soft tissues

Measurement of the strain rate sensitivity of viscoelastic properties is crucial for accurate predictions of the time-dependent behavior of discontinuous biocomposites in soft tissues. The aim of this study is to develop a shear-lag model for elucidating the dynamic response of discontinuous biocomposites in soft tissues under triangular pulse loading and harmonic loading. The extended shear-lag model is focused on improving the previous shear-lag models considering the mass of fiber and including viscoelastic behavior using the Kelvin–Voigt model for the matrix. Analytical expressions of the relative sliding and interfacial shear stress distribution have been presented to characterize the deformation and stress transfer in discontinuous biocomposites under triangular pulse loading. Under harmonic loading conditions, damping properties of discontinuous biocomposites in soft tissues including complex modulus and loss factor are also analytically derived. The predictive model was verified by finite element simulation results. Finally, the results obtained from the shear-lag model are presented to elucidate how the loading rate and loading frequency influence the dynamic response of discontinuous biocomposites. The findings shed light on the dynamic response of soft tissues subjected to impact loading and hysteresis effect under reciprocating loading, which is essential for a better understanding of soft tissue pathology.