Seismic Response Control of Parallel Structures Connectd by Passive Shape Memory Alloy Damper

A shape Memory Alloys are a class of novel functional materials that possess unique properties, including shape memory effect, super-elasticity effect, high damping characteristics, high corrosion resistance, temperature dependent Young modulus and extra ordinary fatigue resistance. In super-elastic phase, shape memory alloys are initially austenitic, upon loading, stress-induced martensite is formed, upon unloading, the martensite reverts to austenite at a lower stress level, resulting in the hysteretic behaviour, is more suitable property for energy dissipation device in structural engineering. In this paper, the response behaviour of two parallel structures coupled by passive Shape Memory Alloy dampers under various earthquake ground motion excitations is investigated. The equation of motion for the two parallel, single-degree-of-freedom structures connected by damper is formulated. The effectiveness of damper in terms of the structural response reduction namely, relative displacement and absolute acceleration of coupled structure is investigated. A parametric study is conducted to investigate the optimum parameter of the dampers. Results show that Shape Memory Alloy dampers connecting the parallel structures of different fundamental frequencies, the earthquake induced displacement response of either structure can be reduce effectively, but acceleration response of flexible structure is increases. Thus passive shape memory alloy damper is not much effective for seismic protection of coupled structure concept.