Bumpers

  The main bumper tasks include the following;

    ·aesthetics；

    ·overall body protection in parking impact (up to a speed of 4 km/h)；

    ·energy absorption and controlled transfer of stress to body frame, when impactedat 15 km/h (insurance impact test)；

    ·aerodynamics;

    ·friendly contact (or absence of injury) in case of pedestrian's impact;

    ·support of winches or tow hooks for off-road vehicles.

    Today most production vehicles have plastic bumpers painted in the same color as thebody; in the case of special mission (e. g. use of bumper to tow or lift heavy masses as incase of off-road vehicles），metal painted or plastic coated bars are in use, stronglyconnected to body；cheap vehicles，to reduce cost and chromatic body matching troubles,feature a different color for body and bumper（in this case bumpers are mass colored,usually grey or black)．

    Bumper shape, gaps with respect to adjacent parts（lamps, fenders, radiator grille,bonnet)，color, roughness are properties relevant to the aesthetics of the vehicle and aretherefore modeled and specified by the styling center. Skin radius must comply with theregulation limit of >2. 5 mm (in some areas>5 mm) for all surface points that can becontacted by a 100 mm sphere. Even the plastic blend used to mold the bumper shouldhave a mass color not so different from the final bumper painted color in order to keep anyabrasion or surface marking less evident.  In some cases, only zones less exposed todamage are painted, while most zones with high risk of contact such as bumper fascia areleft grey or black.

    According toECE 42，bumpers,  both front and rear,  must enable permanentfunctional damage to the vehicle to be avoided when impacted by a pendulum of mass equalto the vehicle curb weight, in three different transverse position and at a height of 445 mmfrom the ground. The vehicle should be tested in three load conditions (curb weight, threepeople and full load)．Pendulum impact speed is 4 km/h or 2. 5 km/h, depending on theimpact position.