Effect of pre-tension in superelastic shape memory alloy on cyclic behavior of reinforced mortise-tenon joints

摘要

A shape memory alloy (SMA) damper made of multiple SMA wires was adopted to reinforce mortisetenon joints. By imposing 0, 1%, and 3% pre-tension in SMA wires before low horizontal cycle reciprocating loading tests, the effects of pre-tension on failure patterns, hysteretic behavior, strength and stiffness degradation, energy dissipation and resetting abilities were studied respectively. In order to describe the hysteretic characteristics of SMA-reinforced joints, analytical study was performed, and the component analysis of the bending moment in different pre-tensioned SMA reinforced joints was analyzed. The results indicated that the large pre-tension could cause the alloy wire breakage. The increase in pretension in the SMA wires could effectively reduce the length of tenon being pulled out and improve the ultimate bearing capacities, but the ductility of the joints was not much promoted. Pre-tension in the SMA wires helped to reduce strength degradation, but had little effect on the degree of stiffness degradation. As the pre-tension increased, the SMA wires provided higher energy dissipation, damping, and resetting abilities for reinforced joints. The predicted values obtained from the analytical study agreed well with the actual behavior, and the component analysis of the bending moment demonstrated that the proportion of the bending moment provided by SMA of 3% pre-tensioned joint was lower than that of the non-pre-tensioned joint at the same rotation angle. (C) 2020 Elsevier Ltd. All rights reserved.