DAMAGE BEHAVIOR OF HONEYCOMB UNDER IMPACT LOADING

Abstract

Honeycomb materials are finding substantial applications in aerospace and automotive industries due to high energy absorption characteristic under impact loading. These applications require a fundamental understanding of crushing behavior of honeycomb and influence of different parameters on energy absorption capability. The present dissertation work illustrates finite element modeling and analysis of honeycomb under impact loading. Shell-163 (4-noded, LS-DYNA) elements are used for modeling 6061 aluminium alloy metal matrix composite honeycomb with variation in cell parameters. Parameters used for investigation are cell shape, cell arrangement, bent radius and included angle. Influence of these parameters has been investigated with respect to impact band formation and - energy absorption during impact. Contact algorithms based on Penalty formulation were adopted so as to avoid cell penetration. Front bumper for car has been modeled and analyzed for its impact behavior. Results exhibit I=band formation at higher cell radius and lower included angle while higher energy absorption- at lower cell bent - radius and higher included angle till 450, and lower energy absorption for more than 45°. Changes in cell shape and cell arrangement have• influence on energy absorption capability of honeycomb. Triangular cell honeycomb has higher energy absorption capability compared to square cell honeycomb. Shift of cell arrangement from regular to stagger reduced absorbed energy. It has been observed that the honeycomb with hexagonal cell shape has higher energy absorption capability compared to square and triangular cell shape. Results show that the bumpers with honeycomb structure as energy absorber minimize deformation of a car body and chassis because much of energy has been absorbed by honeycomb.