Development of an optimal impact energy absorber for highway crash cushions

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Title: Development of an optimal impact energy absorber for highway crash cushions
Author: Michalec, Christopher Ryan
Abstract: The objective of this research is to develop a new and efficient method of absorbing a vehicle ? ?s kinetic energy for highway safety crash cushions . A vehicle that makes a direct impact with a rigid highway structure traveling at highway speeds can be fatal for its occupants . Crash cushions are implemented on roadways in front of these rigid structures with the intent to ? ?soften ? ? the impact . The cushion will bring a vehicle to a stop at safe rates before it impacts the rigid structure . The energy absorbing component of the crash cushion must meet four main requirements . The cushion must reduce the vehicles speed at a rate that does not allow the occupant to impact the vehicle interior at velocities greater than 12 m /s . The cushion must then bring the vehicle to a complete stop with deceleration rates below 20 g ? ?s . A crash cushion must satisfy these requirements for an 820 kg vehicle and a 2000 kg vehicle traveling at 100 km /hr . Advanced design methodologies were applied to enable multiple , innovative design concepts . These concepts made use of the deformation of steel in structural pipe , structural angle , and structural plate to reduce the velocity of a vehicle at a safe rate . Critical design parameters were identified which allowed for efficient and effective numerical experiments to be conducted . The data collected from these experiments were then validated when compared to physical test data . After the data had been collected , each of the designs was compared to one another in order to decide upon the best design . The design selected was the deforming plate concept which makes use of steel plate mounted in a fashion that created two arms that acted similar to two cantilever beams . A wedge was forced beneath these arms deforming them upward . This design is effective because the deformation can be easily controlled by the thickness of the plate , the moment arm created by the wedge , and the geometry of the wedge . Steel plate is a readily available material that requires minimal manufacturing for installation preparation making it cost -effective , and easy to install . In the event of impact with the cushion , new parts will be inexpensive and readily available . Being reusable , easy to repair and low in cost , the energy absorbing concept presented herein is a cost effective alternative to existing energy absorbing technology . Due to replaceable parts being readily available , repair time and cost will be reduced compared to other designs that require new parts to be fabricated for replacement . This will make for a competitive design .
URI: http : / /hdl .handle .net /1969 .1 /2599
Date: 2005-11-01


Development of an optimal impact energy absorber for highway crash cushions. Available electronically from http : / /hdl .handle .net /1969 .1 /2599 .

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