Experimental Characterization and Modeling of the Mechanical Behavior of Architectured Tube-Based NiTi

The aim of the study is to create architectured materials constituted of NiTi tubes combining the intrinsic and novel properties of Nickel-Titanium shape memory alloys with purposely engineered topologies. By joining thin-wall tubes by means of electrical resistance welding, we create regular cellular materials. The superelastic behavior of two architectured materials based on identical tubes but with two topologies are modeled using finite element approaches. Large transformations are taken into account and predicted behaviors are compared by simulating complex loading, exploring the influence of the constitutive material behavior on effective mechanical properties of cellular materials. The parameters of the constitutive equations are identified on tensile tests performed on small dog-bone shaped specimens machined from the tubes by spark cutting. The results of the modeling are at last compared with compression tests performed on these “model” architectured NiTi materials.