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Information × Registration Number 0224U031884, 0121U109857 , R & D reports Title Development of shape memory alloys functional properties prediction methods in systems of structures defense under dynamic loading popup.stage_title Head Yasnii Volodymyr P., Доктор технічних наук Registration Date 29-06-2024 Organization Ternopil National Technical University named after Ivan Puluj popup.description2  The main regularities of the influence of pre-tension quasi-static and cyclic loading on the kinetics of functional properties and durability of the shape memory alloys (SMA) under constant amplitude loading have been studied. The functional properties under cyclic loading include, in particular, recoverable and residual strain, dissipated energy, austenite elastic modulus, and damping coefficient (loss factor). It was found that the damping coefficient decreases significantly during the first ten loading cycles and remains practically constant until the macrocrack initiation. In the stabilization region, the loss factor is almost insensitive to the stress range. For the first time, the effect of partial recovery of the functional properties of a NiTi alloy after a loading step with a higher amplitude was revealed, namely, a decrease in the residual strain of the NiTi alloy with the number of loading cycles at the second stage. It was found that the fracture initiation under the low-cycle fatigue testing of cylindrical specimens of pseudoelastic nitinol occurred from their lateral surface by the quasi-spalling mechanism, which is realized due to the phase transformation of austenite into martensite at a temperature exceeding the completion of the austenitic transformation. Local areas of quasi-spalling found in the fracture nucleation zones of all samples are oriented in the radial direction. Regardless of the stress range, for each asymmetry of the loading cycle, there are decreasing dependences of the effective elastic modulus of the NiTi alloy on the residual strain. Product Description popup.authors Antonov Andrii M. Brevus Vitalii M. Mazepa Mykola R. Medvid Volodymyr R. Myshkovych Olha V. Okipnyi Ihor B. Student Oleksandra Z. Yasnii Volodymyr P. popup.nrat_date 2024-06-29 Close