A mathematical model for a bumper was developed and used to simulate road vehicle impact. A passive friction element was introduced into the bumper system to improve its impact attenuation and kinetic energy absorption capacity. The mathematical model of the bumper-damper system was used to simulate impact phenomena for a 1900 kg mass moving at a speed of 70 km/h (19.4 m/s), 17.5 times the speed of a typical design specification. The simulation revealed that the energy absorption capacity of the bumper was improved with the addition of a friction element. Simple experiments performed confirmed that higher energy absorption could be achieved with the addition of a friction element to traditional bumpers. It was observed that the addition of the friction element to a traditional bumper of a vehicle could increase the critical design speed from 4 km/h (1.11 m/s) to 14.9 km/h (4.1 m/s). That is, a passive friction damper system could be used to attenuate road vehicle impact energy in collisions (of vehicles of mass similar to that of a typical saloon car) at speeds 3 times higher than the speed for which current conventional bumpers are designed to attenuate (i.e. 4 km/h).
Dr. Anthony Agyei-Agyemang is a lecturer at the Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana. He obtained BSc. and MSc. (Diplom) in Mechanical Engineering at the University of Karlsruhe, Karlsruhe, Germany. He obtained his Ph.D. degree at the KNUST, Kumasi, Ghana, in 2010 after research at NC A&T, Greensboro, NC, USA.