Abstract
A phenomenological constitutive model is developed to describe the uniaxial transformation ratcheting behaviors of the superelastic shape memory alloy (SMA) by employing a cosine–type phase transformation equation with the initial martensite evolution coefficient that can capture the feature of the predictive residual martensite accumulation evolution and the nonlinear hysteresis loop on a finite element (FE) analysis framework. The effect of the applied loading level on transformation ratcheting is considered in the proposed model. The evolutions of transformation ratcheting and transformation stresses are constructed as the function of the accumulated residual martensite volume fraction. The FE implementation of the proposed model is carried out for the numerical analysis of transformation ratcheting of the SMA bar element. The integration algorithm and the expression of consistent tangent modulus are deduced in a new form for the forward and reverse transformation. The numerical results are compared with those of existing models; experimental results show the validity of the proposed model and its FE implementation in transformation ratcheting. Finally, a FE modeling is established for a repeated preload analysis of SMA bolted joint.
Highlights
shape memory alloy (SMA) has been widely applied in Micro-Electro-Mechanical System (MEMS), actuators, biomedical devices, organ transplantation, transportation, aerospace, and civil engineering due to its well-known superelasticity, shape memory effect, excellent biocompatibility, and wear resistance [1,2,3,4,5,6]
The results show that all of the phase transformation modulus, the starting stress of martensitic transformation, the hysteresis loop, and the residual strain of NiTi SMA are strongly dependent on the loading rate
A numerical example about the repeated preload process of SMA bolted joint based on the above finite element (FE) model is given; the M6 NiTi SMA bolt is selected in this research
Summary
SMA has been widely applied in Micro-Electro-Mechanical System (MEMS), actuators, biomedical devices, organ transplantation, transportation, aerospace, and civil engineering due to its well-known superelasticity, shape memory effect, excellent biocompatibility, and wear resistance [1,2,3,4,5,6]. Over the last two decades, with a deeper understanding of thermo–mechanical coupling behavior of SMA, more and more scholars have been paying attention to the response of thermo–mechanical coupling behavior of the alloy undergoing cyclic loading. The cyclic deformation behavior of SMA, as described in earlier research, was followed with interested by the research group led by Miyazaki [7,8]. The group’s research concluded that the residual irrecoverable deformation of SMA would increase gradually with the increase of cycle times under mechanical loading cycles. Strnadel et al [9,10] studied the effect of alloy elements and components on mechanical cyclic deformation behavior of superelastic NiTi alloy by experiments, and revealed the inhibition effect of a high nickel content on cyclic residual deformation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
