Superior low-cycle fatigue performance of iron-based SMA for seismic damping application

Cheng Fang, Wei Wang, Yuezhen Ji, Michael C.H. Yam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

This study reveals the superior low-cycle fatigue performance of iron-based shape memory alloy (Fe-SMA) for seismic damping application, catering to the need for more durable, resilient, and perhaps fatigue-free structural systems in seismic active regions. The study commences with material tests examining both the macroscopic and microscopic properties of Fe-SMA under monotonic and cyclic loading, followed by calibration of combined hardening parameters to facilitate numerical modelling. A Fe-SMA shear damper specimen is tested, and its behavior is compared with its mild steel counterpart. Among other findings, the study revealed good ductility of Fe-SMA with a fracture strain of up to 55% under monotonic loading. The fatigue life of Fe-SMA is from 4007 to 83 when the strain amplitude increases from ±1% to ±9%, and the values could be 10 times that of common structural steel. The cyclic strain-life relationships of Fe-SMA can be readily presented by the conventional Basquin-Coffin-Manson relationship. Both kinematic and isotropic hardening characteristics of Fe-SMA are observed, and a combined kinematic/isotropic hardening model with calibrated parameters is shown to adequately capture the hysteretic behavior of the material. The subsequent damper tests provide further evidence of its superior fatigue performance, where a fatigue life of 173 cycles is observed for the Fe-SMA damper under a constant rotational angle of 4%, in contrast to 16 cycles for its normal steel counterpart. The unique phase transformation characteristic of Fe-SMA could also affect the fatigue failure mode, where different crack patterns are observed for the dampers with the different materials.

Original languageEnglish
Article number106817
JournalJournal of Constructional Steel Research
Volume184
DOIs
Publication statusPublished - Sep 2021

Keywords

  • Combined kinematic/isotropic hardening
  • Iron-based shape memory alloy (Fe-SMA)
  • Low-cycle fatigue
  • Seismic
  • Shear damper

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanics of Materials
  • Metals and Alloys

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