Enamel-inspired materials design achieving balance of high stiffness and large energy dissipation

Owing to the unique non-self-similar hierarchical microstructure, enamel achieves the balance of high stiffness and toughness, and in turn provides important ideas for the bio-inspired materials design. In this study, a multiscale numerical study has been conducted to investigate whether the property of high stiffness and large energy dissipation could be duplicated in engineering materials through certain material design principles. Motivated by the structure of enamel, the bio-inspired materials consisting of hard and soft phases were considered, and the designing parameters including the cross-sectional shape, volume fraction, and inclination angle of the reinforcement, and other three parameters related to the waviness of the reinforcement were taken into account. It was found that by employing the non-self-similar hierarchical structure, the designed composites exhibited the balance between stiffness and toughness, which has not been achieved in many engineering materials yet. Furthermore, the influences of the aforementioned designing parameters on the mechanical performance of the composites have been elucidated. The findings of this study have provided a guideline for designing bio-inspired composites achieving the balance between stiffness and toughness.