Concept and hysteretic behavior studies of TWIP steel made metallic energy dissipater

Abstract

Metallic energy dissipaters with good hysteretic performance and high low-cycle fatigue performance are the ideal devices to absorb seismic energy induced in buildings. Generally, two factors domain the performance of axial yielding energy dissipater, which are the configurations and material it adopts. This paper works on those two factors to develop a high-performance metallic energy dissipater. A novel energy dissipater that uses steel tubes as the buckling restrainer is proposed in this paper, furthermore, the twinning-introduced plasticity (TWIP) steel is used to fabricate the key component of the dissipater, the inner rod, because of its exceptional mechanical property. Experimental tests are conducted on a series of 9 specimens that differ in their geometrical length and loading pattern. Test results indicate that all specimens possess satisfying hysteretic behavior, and the low-cycle fatigue performance of this dissipater is better than that of conventional mild steel made ones. Under compressive load, the inner rod forms helical deformation mode whereas deforms uniformly in longitudinal direction under tensile load, and therefore no necking is observed after tests. Basic mechanical properties including the hardening behavior and compressive strength adjustment behavior are investigated quantitatively. A hysteretic model considering the stress hardening property and frictional forces is developed for this dissipater, and good agreement with experimental data is obtained. Finally, deformation pattern and contact evolution of the inner rod are discussed in detail via numerical model.