Impact energy absorption of functionally graded chiral honeycomb structures

Auxetic chiral structures with negative Poisson ratio (NPR) can contract its width along the directions perpendicular to compression loading direction, thus generate enhanced indentation resistance and enhanced impact energy absorption abilities. To enhance the dynamic mechanical performances of periodic anti-chiral structures and hybrid-chiral structures, geometrically graded ligaments are proposed, and the in-plane dynamic deformation mechanism and energy absorption capacity of the functionally graded anti-chiral and hybrid-chiral cellular structures are studied through finite element analysis (FEA). Numerical results in our work show that the crushing energy absorption performances of periodic chiral structures can be improved by introducing structural graded design, where the plateau stress and energy absorption efficiency can be optimized by means of adjusting the unit cell geometrical parameters. Our study can enrich insightful understanding of the dynamic behavior of chiral cellular materials, and can be employed for optimizing the design of automobile crash energy absorption and impact protection structures. (C) 2019 Elsevier Ltd. All rights reserved.