Constitutive modeling of cyclic behavior in shape memory alloys

Cyclic mechanical behavior of SMAs in some different loadings is numerically studied and experimentally verified. A phenomenological approach based on microplane theory is proposed to develop an original constitutive model. In the extended model, effect of loading history on the transformation thresholds is demonstrated. NiTi thin-walled tubes are experimentally investigated to evaluate the effect of loading history on the transformation start conditions of the superelastic shape memory alloys. Some consecutive loading cycles are experimentally applied during forward and reverse transformations. Experimental cyclic interruptions are applied during loading-unloading paths and are compared with numerical results. Numerical correlations between extended microplane model and experimental results demonstrate the success and accuracy of the extended model. These results confirm that the new model with new transformation conditions is capable of simulating the cyclic mechanical response of SMAs. (C) 2015 Elsevier Ltd. All rights reserved.