Study on impact resistance of nacre biomimetic composite under interlamination functional gradient design

Functional gradient is an effective way to improve the impact resistance of materials. The combination of functional gradient and brick-mud structure is also considered as a potential research direction of nacre structure. Based on this, a design scheme of nacre biomimetic composite (NBC) with interlamination functional gradient is proposed in this paper. The hard component of NBC is formed by scattering random discrete points to construct Tyson polygon, and the number of random discrete points in each layer forms an increasing or decreasing interlamination gradient. The impact response of pendulum was simulated by FEM. By comparing and analyzing the impact response results of different functional gradient groups (positive gradient, negative gradient and non-gradient), the influence mechanism of functional gradient on energy absorption properties of NBC is revealed. The results show that the positive gradient group K70 has the strongest impact resistance, the peak impact reaction force is increased by 34% and the energy absorption value is increased by 51% compared with the non-gradient scheme. The positive gradient can make full use of the stiffness of hard component and the elasticity of soft component, so that NBC has a more reasonable energy distribution and improves the impact resistance of the whole NBC structure.