The main responsibility of bumper is to protect pedestrians: because pedestrians are vulnerable groups, plastic bumper can alleviate the impact force on the legs of pedestrians, especially the calves, with the reasonable design of the front bar, reduce the degree of injury when pedestrians are hit.
Secondly, it is used to reduce the loss of vehicle parts in speed collision. If the bumper is poorly designed, the damage to these parts can be severe in a crash.
Why are the bumpers plastic and filled with foam?
In fact, bumper was indeed made of steel a long time ago, but later it was found that the function of bumper is mainly to protect pedestrians, so it is natural to change to plastic.
Some crash-proof steel beams will be covered with a layer of foam, which is to fill the gap between the resin bumper and the crash-proof steel beam, so that the bumper is not so "soft" from the outside, the actual effect is at very low speed, very slight force, can be directly free of maintenance.
The lower the bumper, the higher the repair cost:
The higher the bumper design, the lower the repair costs, according to the IIHS report. Many cars due to the very low design of the bumper, when the collision with the SUV, pickup truck is not a buffer role, the damage of other parts of the vehicle is also relatively large.
Front bumper repair costs are higher than rear bumper repair costs are significantly higher than rear bumper repair costs.
One is that the front bumper involves more parts of the car, while the rear bumper only involves relatively low-value components such as taillights, exhaust pipes and trunk doors.
Second, because most models are designed to be low in the front and high in the back, the rear bumper has a certain advantage in height.
Low-strength impact bumpers can cope with the impact, while high-strength impact bumpers play the role of force transmission, dispersion and buffering, and finally transfer to other structures of the body, and then rely on the strength of the body structure to resist.
America does not regard bumper as a safety configuration: IIHS in America does not regard bumper as a safety configuration, but as an accessory to reduce the loss of low-speed collision. Therefore, the testing of bumper is also based on the concept of how to reduce the loss and maintenance cost. There are four types of IIHS bumper crash tests, which are front and rear frontal crash tests (speed 10km/h) and front and rear side crash tests (speed 5km/h).
