F4-J Dynamic Crushing of Regular, Irregular & Functionally Graded Cellular Structures

Abstract: The in-plane dynamic crushing of two dimensional honeycombs with both regular hexagonal and irregular Voronoi arrangements was investigated using detailed finite element models. The crushing behavior and energy absorption of honeycombs made of a linear elastic-perfectly plastic material with constant and functionally graded density were studied up to large crushing strains. Our numerical simulations showed three distinct crushing modes for honeycombs with a constant relative density: quasi-static, transition and dynamic. Moreover, irregular Voronoi cellular structures showed to have en-ergy absorption similar to their counterpart regular honeycombs of same relative density and mass. To study the dynamic crushing of functionally graded cellular structures, a relative density gradient in the direction of crushing was introduced in the computational models by a gradual change of the cell wall thickness. Decreasing the relative density in the direction of crushing was shown to remarkably enhance the energy absorption of honeycombs. The results provide new insight into the behavior of engineered and biological cellular materials, and could be used in development of a new class of energy absorbent cellular structures.

Faculty and Staff Currently Involved in Project:

Ashkan Vaziri
Professor
Northeastern University

Students Currently Involved in Project:

Amin Ajdari, PhD
Northeastern University