Experimental study and modification of the constitutive model of superelastic SMA considering multi-factor effects

The constitutive model is the basis and key for the application of materials in practical engineering. Numerical simulation has become one of the most important methods of scientific research, and an accurate constitutive model provides guarantees for the efficiency of numerical simulation. The multi-linear constitutive model is one of the most useful models for engineering. In this paper, different diameters of superelastic Shape Memory Alloy (SMA) wires are selected to investigate mechanical properties through experimentation. The influences of diameter, loading rate, temperature, and loading amplitude on the phase transformation stress, elastic modulus, residual strain, and energy dissipation properties are researched individually, and then the expressions of the influence law are given. Correction coefficients considering the effects of diameter, loading rate, temperature, and loading amplitude are employed to modify the multi-linear constitutive model. A multi-linear dynamic constitutive model considering multiple influence factors is given. Finite element analysis is carried out by introducing the modified multi-linear dynamic constitutive model into the finite element software, and the simulation results are compared to the testing results. The modified multi-linear dynamic constitutive model has high accuracy and can guide the engineering and numerical studies.