At present most of the Indian vehicles are fitted with rigidly mounted bumpers without energy absorbing devices. An alternative to the rigidly mounted bumper is considered by designing and developing various energy absorbing devices and energy attenuators such as elastomers in various shapes and sizes, the collapsible, sheet metal fenders, metal flat springs and the ‘U’ type energy attenuator. The various factors such as aerodynamics, aesthetic, easy removal and mounting of the bumpers were also considered while designing and fabrication of the bumpers.
The sheet metal and Fibre Reinforced Plastic (FRP) bumpers are designed and fabricated in four different types with various combinations of elastomers, energy absorbing devices and attenuators.
A major emphasis is given on low cost fabrication of three dimensional bumper shell, dies, moulds, collapsible and energy absorbing device. Various designs of the bumpers are evaluated with the help of pendulum impact test rig by making additional provision to find out the impact load and the deflection transmitted at the mounting point of the vehicles which gives additional information to the vehicle designers.
The paper covers various designs, methodology used for low cost prototype fabrication and the testing and evaluation of bumpers simulating 8 km/hr impact. The data presented also gives the relative weight of various thicknesses of the bumpers and the energy absorbed during impact and transmitted on vehicle mounting point.