1) What is a bumper?
A bumper is a shield made of steel, aluminium, rubber, or plastic that is mounted on the front and rear of a passenger car. When a low speed collision occurs, the bumper system absorbs the shock to prevent or reduce damage to the car. Some bumpers use energy absorbers or brackets and others are made with a foam cushioning material.
Bumper systems have changed drastically over the last 20 to 30 years. More demanding government safety regulations and different styling concepts have resulted in new designs.
Materials have also changed dramatically. With emphasis on vehicle performance, High-strength and ultra high-strength steels were developed. These permitted designers to reduce sheet metal thickness, hence weight. For reasons of low cost and light weight, steel is well positioned in the current bumper system market.
There are several factors that we must consider when selecting a bumper system.
The most important factor is the ability of the bumper system to absorb enough energy to meet the OEM's internal bumper standard. Another important factor is the bumper's
ability to absorb energy and stay intact at high-speed impacts. Weight, manufacturability and cost are also issues that we as an engineer consider during the design phase. Both initial bumper cost and repair cost are important. The formability of materials is important for high-sweep bumper systems. Another factor considered is recyclability of materials, which is a definite advantage for steel.
There are four common bumper systems to use today:
ÃÂ· Metal facebar
ÃÂ· Plastic fascia and reinforcing beam
ÃÂ· Plastic fascia, reinforcing beam and mechanical Energy absorbers
ÃÂ· Plastic fascia, reinforcing beam and foam or honeycomb energy absorber
Metal facebar system consists of a single metallic bumper that decorates the front or rear end of a vehicle and acts as the primary...