Smart materials such as shape memory alloys (SMAs) are recently being used in earthquake engineering applications to control the response of structures. In this paper, a shape-memory alloy damper device made up of austenite wires (e.g. Nickel Titanium wires) is used as a passive energy absorber. NiTi wires are very attractive for passive vibration control as they have a pseudo-elastic property and can sustain large amounts (upto 10% strain) of inelastic deformation. Moreover, in contrast to regular metallic materials they can recover that deformation. The damper device is designed, fabricated and tested. Validity study is made using a thermo-mechanical model of SMA taking into account the residual martensite accumulation irreversibly due to cyclic forward/reverse martensitic transformation. Further an analytical study of a supporting steel structure of dump tanks with and without SMA dampers subjected to design wave earthquake loading is carried out. Performance of the structure with SMA dampers is compared with that of the same structure with yielding dampers.
Research and development of seismic response control devices has gained prime importance recently, due to an increased number of devastating earthquakes. Passive control systems are now accepted all over the world and hence research in this area is continuing to develop reliable, efficient and cost effective devices along with constitutive modeling. This paper begins with qualitative description and comparison of passive, active and semiactive control systems. Further, it mentions advantages of passive control systems over the others. A detailed literature review of passive devices is then provided which includes the historical development of the devices, their dynamic behavior, testing of these devices incorporated in the structural models and their analytical formulations. The pros and cons of these devices in retrofitting of structures and their first and recent applications in a wide variety of structures are also discussed. The passive response control systems that are discussed include viscoelastic dampers, yielding dampers, viscous dampers, friction dampers, tuned mass dampers, tuned liquid dampers, tuned liquid column dampers, superelastic dampers, like shape memory alloy dampers and base isolators.
This study uses the pseudoelastic properties of Ni–Ti shape memory alloy wires for attenuation of the seismic response of a steel structure and evaluates its effectiveness and applicability in seismic response control. In this paper, shake table tests, carried out on a model of a steel structure with and without wire-based shape memory alloy dampers, are discussed in detail. Shake table tests, comprised of free vibration tests and spectrum compatible time history tests, were carried out. The former were used for the evaluation of the frequency and damping, and the later were used to prove the efficacy of the shape memory alloy dampers. Further analytical simulations are carried out using detailed time history analysis utilizing a thermomechanical model of an SMA and taking into account the residual martensite accumulation, which is irreversibly due to cyclic forward/reverse martensitic transformation. Moreover, a simple iterative response spectrum (IRS) method with equivalent damping and stiffness is also used to evaluate the response of the structure with SMA dampers, and it is proved that the method can be conservatively used by designers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.