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Static and Dynamic Tests of An Axially-Collapsing Structure Concept of a Front End Energy Absorber for a Vehicle
Published January 01, 1986 by Yugoslavia Society of Automotive Engineer in Serbia
Cylindrical columns/round section rails have been found to possess greater energy absorption, weight efficiency and crush folding stability than other shapes, for example, squares or rectangles.
The stucture described in this paper represents a design concept of a vehicle front end energy absorbing member, here, simplified to facilitate experimentation and analysis, which utilizes round section rails for a controlled axial collapse mode. Two rails, 36" long, 3.5" in diameter and 0.038" thick, were made of 980 XK high strength steel and were mounted on a truss-type backup structure simulating an interface with the passenger compartment. The rails were designed to be capable of absorbing 50% of the kinetic energy of a 1550 lb vehicle crashing at 40 mph into a fixed barrier. The structure was statically crushed, exhibiting a stable progressive mode of collapse. The dynamic performance of the structure was evaluated in two steps: it was first crashed to simulate a 35 mph impact with a fixed barrier, and then recrashed to simulate in the aggregate a 40 mph barrier impact. The structure folded progressively and stably, achieving the design goal.
This paper describes the static and dynamic crush experiments on the energy absorbing rail elements, subassemblies, and the complete assembly. Highlights of the test results are presented. Finally, applications of this rail design concept to other vehicle structural components are discussed.