![]() ![]() After that, the collapse, or crush zones, of the frame rails must come into play. A small portion of the energy is absorbed by the low-speed design aspects of the bumper system. To protect the passengers, collision energy must be directed into areas of the vehicle that can dissipate the energy before it reaches the passenger area. The rigid reinforcement bar is the primary element in these instances. If the impact energy, which is a function of the mass of the vehicle and the speed of the impact, is low enough, this system will work and require minor repairs, such as replacing the absorber material, repairing any scratches to the cover, and painting.ĭuring higher-speed collisions, the bumper system serves an entirely different purpose. In low-speed impacts, the bumper system absorbs energy by flexing the cover, crushing the absorber and collapsing the mounts. These mounts may be complex hydraulic devices designed to absorb minor impacts and rebound, simple metal mounts designed to bend and be replaced after minor impacts, or the end of the frame rail may serve as the mount. The reinforcement is mounted to the frame rails. A rigid reinforcement bar, often called a re-bar, is located behind the absorber. This part is made of plastic and is intended to collapse in minor impacts to absorb the energy. In low-speed impacts, the cover can bend and flex back. Spoilers may be incorporated into the design or attached to the cover. Openings for air flow to the cooling system, housing for lights, and mounting for license tags may be designed in. The cover is usually made of plastic and functions largely as a style element. These elements can be quite different from vehicle to vehicle, but the functions are the same. More information on these tests can be found atīumper systems are made up of four elements: the cover, absorber, reinforcement bar and mounting system. Various tests performed by the IIHS demonstrate that minor impacts can cost a few hundred to several thousand dollars to repair, depending on how the bumper system is designed. The Insurance Institute for Highway Safety (IIHS) devotes time to studying low-speed bumper performance. Complex plastic covers, lights housed inside the bumper, and very close integration with the hood and fenders, complicate repairs. Since many accidents are low-speed-or parking lot-collisions, this is an important consideration. Low-speed impact performance is one function of bumper systems and is measured by how expensive “minor” impact repairs are. The line between passenger cars and trucks today has been blurred. Further complicating the comprehension of this standard is that it was not applied to trucks. That standard was later changed, and for 1983 and later vehicles it is now 2.5 mph. A property damage standard became effective in 1979, prohibiting damage except to bumpers and their attachments in 5 mph flat-barrier tests. Engineers are challenged to design an aesthetically pleasing, yet functional system that will not be excessively expensive to repair in minor collisions-or too heavy.įederal standards for bumpers began in the 1970s. They also still serve to protect the vehicle during low-speed impacts. Modern bumpers systems include many parts that serve several purposes, the main one today being to provide protection to the vehicle’s occupants. When faced with an unfamiliar component design, be sure to check the vehicle manufacturer’s recommendations for damage inspection and replacement recommendations. Deeper inspection should almost always be done to be certain all of the safety features are also addressed. Evaluating bumper systems is not difficult, but it is more important than might be obvious to the casual observer. ![]()
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