Functional fatigue study of a TPMS structure made of niti under cyclic loading

This work is focused on a TPMS primitive unit cell, modeled with NiTi as a base material and subjected to cyclic loading. Its functional fatigue behavior is analyzed via an FEM model, and the appropriate post-processing of the data. Full periodic boundary conditions are applied onto each of the cell's faces, to simulate an infinitely-large structure. The loading and unloading surfaces, from the first unloading onwards, depend on the accumulation of the martensite phase, due to a residual stress field. This effect, functional fatigue, is taken into account to derive loading and unloading surfaces via double interpolation. This double interpolation is done from the information of calibration cases. Then, it is validated with a different loading path. This facilitates the prediction of the functional cyclic behavior of primitive TPMS cells made of NiTi.