Design of shape memory alloy pipe couplers: modeling and experiments

Shape memory alloy (SMA) pipe couplers use the shape memory effect to apply a contact pressure onto the surface of the pipes to be coupled. In the current research, a SMA pipe coupler is designed, fabricated and tested. The thermally induced contact pressure depends on several factors such as the dimensions and properties of the coupler-pipe system. Two alloy systems are considered: commercially-available NiTiNb couplers and in-house developed NiTi couplers. The coupling pressure is measured using strain gages mounted on the internal surface of an elastic ring. An axisymmetric finite element model including SMA constitutive equations is also developed, and the finite element results are compared with the experimental results.