Patent ID: 7648589
Filing Date: 2010-01-19
Classification: B22F,C25D,Y10T

Abstract:
1. An energy absorbing structure comprising a first shape memory alloy (SMA) member and a second SMA member, wherein the first SMA member is disposed externally of the second SMA member, spaced apart by a gap from the second SMA member when the energy absorbing structure is not subjected to any stress, and configured to constrain the second SMA member so as to increase a buckling load that the second SMA member can accommodate, the second SMA member comprising a super elastic and ductile sintered SMA exhibiting a porous microstructure, in which interstitial spaces separate adjacent SMA particles, the porous second SMA member exhibiting a trapezoidal stress-strain curve response characteristic of an equivalent SMA exhibiting a dense microstructure under compressive testing performed above an austenite finishing temperature, a performance of the energy absorbing structure being enhanced due to a super elastic deformation of the second SMA member as the second SMA member is stressed about at least two substantially orthogonal axes sufficiently to close the gap, so that the second SMA member contacts and is constrained by the first SMA member.