The Simulation and Experimental Study on Expansion Deformation of the TiNiFe Shape Memory Alloy Pipe Coupling

TiNiFe shape memory alloys are frequently employed in the construction of aircraft hydraulic pipelines, due to their exceptional recovery performance. This study is to address the issues of inconsistent dimensions and the challenge of accurately characterizing the expansion state of pipe couplings following expansion. A finite element simulation model of the cryogenic temperature expansion process has been constructed using the Abaqus platform. The effect of expansion ratio on the stress–strain state and dimensions of the pipe coupling throughout the deformation is subjected to comprehensive examination. The results demonstrate that the axial stress at the inner convex is the greatest, exceeding 400 MPa. As the expansion ratio increases, the axial deformation of the pipe coupling along the expansion direction intensifies, and the radial stress rises. The combined effect results a significant increase in the expansion load. At an expansion ratio of 12%, the maximum Huber‐von Mises stress exceeds 1000 MPa, resulting in plastic deformation at the inner convex. Furthermore, the calculation model is modified based on the original tubular parts expanding force calculation formula, and a method for calculating the expanding force of the pipe coupling is established. The combination of expanding force calculation and finite element simulation enhances the precision.