Performance Research Of Steel Structures Based On Elobow Type SMA Energy Dissipation Device

Shape memory alloy(SMA)is an intelligent metal material with the super elastic properties and shape memory effect.In recent years,the SMA materials have been widely studied and applied in the field of building structures.In shock absorption structures,the SMA with the special super elastic properties and shape memory effect which can not only dissipate part of the energy under earthquake,but also provide certain resilience for building structures and reduce the residual deformation of structures.However,the super elasticity of SMA materials requires a certain displacement.Due to the limited displacement of ordinary braced mechanism,the shock absorption and energy dissipation of the SMA materials can not be fully exerted.Therefore,an elbow SMA damper is proposed to give full play to the properties of the SMA.In addition,the seismic performance of steel frame structures under the different sites of earthquake action is studied and the main research contents are as follows.(1)The relationship between super elastic properties of the SMA and temperature and stress as well as the relationship between the shape memory effect,temperature and strain are studied.It is shown that the envelope area of the hyper elastic performance curve can be changed by the change of stress.However,the change of temperature only affects the upper and lower bounds of the hyper elastic curve,and does not change the envelope area.The shape memory alloy restores its original shape after unloading.(2)A new SMA damper with energy dissipation and self-resetting capability is designed,and its working principle and characteristics are introduced.At the same time,a kind of elbow-type displacement amplification mechanism is proposed.What's more,the relationship between the displacement amplification factor and the elbow angle is derived.Finally,the suggested elbow SMA damper can reduce the displacement response of the structure.(3)Using seismic waves from different sites to analyze the response of Benchmark steel frame model with or without dampers.Then the responses of uncontrolled structures,braced SMA dampers and elbow type SMA dampers under earthquake as well as theseismic absorption effect of the structure under different damper arrangement schemes are compared.It shows that the elbow SMA damper can effectively reduce the dynamic response of the structure.While reducing the number of dampers,the arrangement of weak layer can achieve better control effect.