Abstract: A thermal stress-free joint assembly for joining a low thermal expansion member and a high thermal expansion member uses a fastener and a bushing fitted within a bore in the low thermal expansion member, wherein the fastener and bushing materials are selected to have predetermined coefficients of thermal expansion. The fastener includes a shank which passes through the bore in the low thermal expansion member. The bushing, bore and shank are dimensioned according to a mathematical relationship to maintain a predetermined clearance or preload as the joint undergoes changes in temperature, without damage to either joined member from thermally induced stress.

Abstract: A rotary actuator with tailored torque output comprises a shape memory alloy rod or tube encased within or filled with a burnable chemical grain. In its initial state, the rod or tube has zero degree rotation about its longitudinal axis. The rod or tube is then rotated or twisted about its longitudinal axis when the shape memory alloy is in a malleable state. The rod or tube may be progressively, selectively heated by the burning of the chemical grain to cause the shape memory alloy to return locally to its original shape with the consequence that a free end of the rod or tube is rotated.