Nonlinear mechanics and optimization design of bioinspired heterostructures
Designing lightweight structures with high strength and toughness is a fundamental scientific problem in mechanics and materials science and an everlasting theme in engineering applications.Through millions of years of evolution,biological materials have developed delicate structures with stronger,tougher and lighter mechanical properties,which have become templates for the design of high-performance engineering materials.However,biological materials are often composed of multiscale and hierarchical structures and interfaces that display nonlinear and multiprocess deformation and fracture behaviors,which in turn determine their mechanical properties,such as strength and toughness.The development of nonlinear mechanical models to elucidate the fundamental nonlinear structure-interface-property relationships in biological materials and to provide optimized designs for high-performance biomimetic materials is key nonlinear mechanical issues.This paper provides a featured review of the representative biological"brick and mortar staggered structure"and"twisted fibrous structure".This review first discusses the nonlinear mechanical models and structure-interface-property mechanisms for representative volume element(RVE)of bioinspired heterostructures.Then,the fracture behaviors and their correlation with the mechanics of RVE are demonstrated in bioinspired heterostructures with cracks.Furthermore,based on the above mechanical models and mechanisms,some design schemes are proposed to optimize mechanical properties,such as strength,toughness,kinetic energy dissipation,and fracture toughness.Finally,the remaining challenges and future perspectives for the nonlinear mechanics and optimization design of bioinspired heterostructures are proposed.