Go Murasawa1, Satoru Yoneyama2, Toshio Sakuma3 and Masahisa Takashi4
1Department of Mechanical Engineering, Yamagata University, Yonezawa 992-8510
Many problems have existed in usage of shape memory alloy (SMA) such as the appearance of unexpected deformation behavior under complicated thermo-mechanical loadings. Inhomogeneous deformation behavior of SMA is one of the causes in those problems. The aim of the present paper is the investigation of inhomogeneous deformation behavior arising in SMA during cyclic loading. Firstly, a test system measuring inhomogeneous deformation behavior was constructed on the basis of Digital Image Correlation (DIC). Secondary, measurements of inhomogeneous deformation behavior (local strain distribution) arising in 50.5Ni49.5Ti plates were conducted during cyclic tensile loading-unloading at the temperature region of pseudoelasticity. It was seen that inhomogeneous deformation behavior sensitively changed according to state of loading (i.e., number of cycle, history of loading and so on). Also, macroscopic deformation behavior was strongly affected by inhomogeneous deformation behavior. It is very important for application of SMA to investigate the relationship between macroscopic deformation behavior and inhomogeneous deformation behavior.
NiTi shape memory alloy, pseudoelasticity, inhomogeneous deformation behavior, local strain, cyclic loading, digital image correlation
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