Numerical Analysis on Crashworthiness Design of Thin Walled Columns under Dynamic Impact Loading Conditions

Abstract

Transportation and automobiles have become a part of our daily lives and the risks associated with them of unwanted collision have also increased with automobiles being manufactured at a very high level all over the world. With the increasing trend of fatalities and injuries caused by the road traffic accidents, making the vehicles safer has become more critical. In the early years vehicle were made of solid metals and heavy frames which provided enough occupant protection but with time the need of making vehicles fuel efficient the low weight requirement has changed the manufacturing era of automobiles. Although we cannot avoid the occurrence of unwanted collisions but the impact and severity of crash can be reduced. Thin Walled Columns are extensively being used in various engineering applications for the purpose of safety requirements due to their high energy absorption capacity. Their primary purpose is to absorb the excess amount of impact energy during an unwanted collision undergoing deformation. Numerical analysis of crushing behavior using Finite Element Module LS-DYNA is carried out to study the best performance parameters which are specific energy absorption (SEA), mean crushing force (MCF) and low peak force (PF) by varying different design variables including cross sectional geometry, thickness and length. The objective is to find the best optimal crash box which undergoes progressive deformation to absorb collision energy for the application in automobiles to enhance the safety for passenger cabin. To study the effect of number of corners on crashworthiness parameters, polygons having 5 to 8 corners are numerically analyzed and the best of them is further numerically investigated with circular, rectangle and square cross sectional shape. Thin walled tube having hexagonal cross section is found to be the best for energy absorption under axial impact loading while comparing selected crashworthiness parameters.