Energy management system and method for an extruded aluminum vehicle subframe

An energy management system and method for absorbing and directing kinetic energy during an impact event of a motor vehicle includes a vehicle subframe 30 attached to a vehicle chassis 20, with a pair of deformable attachment brackets 40 and 42 interposed therebetween. The deformable attachment brackets 40 and 42 are preferably fixedly attached to the subframe 30 and removably attached to the vehicle chassis 20 via fasteners 50 extending through a fastener hole 52 in each of the attachment brackets 40 and 42. A relief opening 54 is proximate to and aligned with the fastener hole 52, the relief opening 54 being larger than the fastener 50. A deformable barrier 56 disposed between the fastener hole 52 and relief opening 54 may be provided with a slot 58 extending between the fastener hole 52 and relief opening 54. Upon an impact generating an impact force above a predetermined force, the fastener 50 deforms the deformable barrier 56, whereby the deformable attachment bracket 40 and 42 is displaced longitudinally such that the fastener 50 is relocated from the fastener hole 52 into the relief opening 54. The fastener 50 slides out of the relief opening 54 and the subframe 30 drops beneath the vehicle chassis 20, whereby the subframe 30 translates longitudinally relative the vehicle chassis 20 during the crash event, safely away from the vehicle occupant compartment.