Mass Efficient Front Crush Can Design 2011-01-0769
Crush cans are used as replaceable energy absorbing devices that minimize the damage to the front motor compartment main structural rails during a low speed crash event. This is done in an effort to reduce insurance repair costs, which is especially important in Europe where DANNER/TIC insurance ratings drive consumer cost of ownership and may influence the purchase selection.
There are multiple approaches to crush can designs and methods of attachment to the motor compartment rails. One such approach is to utilize a “stick-in” design where the crush can is inserted into the rail section then bolted from the sides. Such designs typically require extra back-up brackets inside the main rails to help provide an adequate reaction structure that allows the desired crush initiation to occur within the can and prevent premature yielding in the main rails during a low speed crash incident. These added brackets, however, translate into additional mass and cost to the vehicle.
This paper summarizes the design and development of a more cost effective, mass efficient approach to the “stick-in” crush can concept that is independent of both material and forming technology. The proposed design eliminates the need for any added brackets leading to about 21% mass reduction and approximately 8% cost savings from a baseline stick-in crush can design that uses the brackets. Care was taken to ensure that other system performance requirements such as structural stiffness and high speed crash energy management are unaffected.