Frequency-dependent dynamic moduli prediction for general bio-inspired staggered platelet reinforced composites

Load-bearing biological staggered composites, like nacre, teeth, and bone, possess an exceptional combination of material properties like high stiffness and high toughness. To date, most of the analytical research are for nacre-like bio-inspired staggered composites, with highly overlapped platelets. But the collagen fibril-like staggered composites, with slender or barely overlapped platelets, are out of their scope. This motivates this work. In this paper, based on the previous research, according to the elastic-viscoelastic corresponding principle, an analytical model for dynamic properties of general bio-inspired staggered composites is presented. Moreover, the effect of loading frequency in a wide range is studied. The accuracy of the model is verified by comparison with existing models and finite element simulations. Besides, parametric analyses and sensitivity analysis are conducted thoroughly. The results reveal that besides the platelet concentration and the platelet aspect ratio, the platelet overlap ratio also influences the damping behavior of bio-inspired staggered composites to a certain extent; for biological/biomimetic composites with a larger overlap ratio, higher loss modulus is possible to be achieved, and the optimal aspect ratio is mostly within [5, 30]. These findings are of great significance to the optimal design of bio-inspired engineering materials in the future.