The car bumper system is an integral part of the car body, forming a four-tiered protection system: outer panel, buffer layer, crash beam, and energy-absorbing box. Modern bumpers typically consist of an outer panel, buffer material, crash beam, and energy-absorbing box. The outer panel is made of PP polypropylene plastic, the buffer layer is honeycomb foam or an energy-absorbing structure, the crash beam is made of steel or aluminum alloy, and the energy-absorbing box is a collapsible metal component. This system absorbs impact energy and protects vehicle components during a collision. It can automatically recover after a minor collision and disperses impact force in a severe collision to ensure occupant survival space. Its design also serves a decorative function.
In low-speed collisions, it plays a major role in energy absorption and must meet pedestrian protection requirements. Bumper materials have evolved from metal to plastic. In 1971, the National Highway Traffic Safety Administration (NHTSA) in the United States issued the world's first technical standard regulating car bumper design. In 1976, under the relevant regulatory framework, bumper standards were divided into "Phase I Standards" and "Phase II Standards." In 1983, US bumper regulations were further relaxed. Plastic bumpers can reduce production costs by 20%-30% compared to metal bumpers.