Poisson ratio can play a crucial role in mechanical properties of biocomposites

Analytical models and complementary finite element (FEM) calculations are developed to evaluate the influence of Poisson ratio on the mechanical properties of biocomposites with staggered mineral platelets in parallel alignment in a soft protein matrix. As the Poisson ratio of the soft matrix is increased towards the incompressibility limit 0.5, the staggered biocomposites are significantly stiffened in both longitudinal and transverse directions, with the transverse stiffness increasing by more than two orders of magnitude. Since the Poisson ratio of most soft biological tissues is very close to 0.5, it is concluded that the Poisson ratio can play a crucial role in the mechanical properties of biocomposites. Based on the theoretical analysis, some discussions are made on several mechanisms that are responsible for the superior properties of biocomposites.