Shape memory alloy (SMA)-cable-controlled sliding bearings: development, testing, and system behavior

Abstract

This paper presents an innovative type of friction sliding bearing system incorporating shape memory alloy (SMA) cables. The study commences with cyclic tests on individual SMA cables to understand their fundamental mechanical properties. The working principle of the proposed SMA-cable-controlled friction sliding bearing (SMA-sliding bearing) is subsequently described, followed by physical tests on two SMA-sliding bearing specimens. The bearing specimens show rectangular hysteresis loops induced by Coulomb friction before the SMA cables are stretched, and afterward the load resistance and energy dissipation capacity of the bearings are increased accompanied by certain self-centering capability due to the engagement of the SMA cables. Such action is expected to effectively restrict excessive displacements of the bearings and to help reduce the residual displacement. Following the experimental study, a theoretical model of the new bearing is developed and numerical simulation is carried out. The theoretical and numerical results agree very well with the experimental results. A case study focusing on a three-span continuous bridge subjected to pulse-like near-fault (NF) ground motions is subsequently conducted, where three types of bearing system, namely, conventional sliding bearing system, SMA-sliding bearing system, and steel-cable-controlled (steel-sliding) bearing system are compared. The system-level analysis results show that the proposed SMA-sliding bearing has its superiority in superstructure displacement control, with a limited increase in the curvature ductility of the pier.

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

“…The fundamental period (T), which is 1.04 s for the present bridge, could be obtained by modal analysis. 26 When an appropriate value of α is chosen, the total force provided by SMA cables can be calculated, and then the corresponding cable area A sum can be calculated through Equations ( 1) through (16). In this project, α is assumed to be 0.65 to satisfy the proposed design criteria based on a preliminary analysis, and the calculated SMA cable area for each bearing is 554 mm 2 , corresponding to ten 7 × 7 × 1.2 SMA cables.…”

“…25 In addition, a large number of restrainers are often required to avoid yielding, resulting in an increased impact to the substructure when the cables are suddenly stretched. 26 Corrosion is another issue that affects the service life of the steel cable restrainers.…”

“…SMA elements with larger load resistance, for example, SMA cables, may be more feasible for isolation bearings. 26,53 While there has been encouraging progress on SMA-based isolation bearings, most of the existing studies focused on numerical analysis, whereas test evidence, especially full-scale tests, is very limited. Practical issues such as effective gripping and installation details cannot be fully reflected by the numerical studies.…”

Machine Learning Enhanced Dynamic Response Modelling of Superelastic Shape Memory Alloy Wires

“…Moreover, Liu et al [ 2 ] proposed a base isolation system by incorporating springs made of superelastic SMA wires. Apart from this, Liang et al [ 3 ] used cables composed of SMA wires to enhance the effectiveness of a friction sliding bearing. A review and detailed summary of the related applications can be found in [ 4 , 5 , 6 ].…”

Seismic Metamaterials With Tensegrity Architecture

“…These SMA wires act as energy dissipators inside the braces because of their shape memory effect and super-elastic effect without having major deformation [11]. When stretched, the energy is dissipated in a considerable amount [12]- [14]. Further SMA effect of the wire amplifies the even infinitesimal movement in bars thus acting as sensors for energy dissipation device.…”