The Earthquake Response Analysis Of Re-Centring Isolation Structure With Shape Memory Alloys

The structure vibration control is a new method of anti-earthquake in civil engineer. Because of the mature theory, the base isolation is adopted widely. Since the shape memory alloys re-centring damper is provided with hysteretic curve in the "double flag" type, to suppress the response of structure and get the capacity of fully re-centring, the new isolation system combining the above damper with laminated rubber bearing is proposed.To illustrate the feasibility and verify the isolation and re-centring effect of the above system, a series of theory analysis and calculating program is presented in this paper. The following work is done:First, because the constitution relation of shape memory alloys is expressed by differential equation, solving the equation becomes unusual complex. The method of bisection is introduced to carry though value calculation, in this way, the relation of stress and strain is revealed. Secondly, the specific configuration and functioning principle of shape memory alloys re-centring damper is introduced. The mechanical property of damper under static reversed loading is analyzed by program, and the hysteretic curve is obtained. In order to meet the requirement of simplifying and precision, a linear restoring model is put forward. Then, the elasto-plastic time history analysis for re-centring isolation structure with shape memory alloys is carried out, and compared with fixed structure the control effect and fully re-centring capacity of the new isolation system is verified. In addition, the influence of restoring model parameter is illustrated, so the principle of selecting above parameter is gained. At last, according the present seismic code, the simplified design method for structure with shape memory alloys re-centring isolation device is introduced.The study result is listed as follow: The transformation pseudo-elasticity property of shape memory alloys is simulated exactly with the above mentioned method of value calculation. The shape memory alloys re-centring damper presents typical "double flag" hysteretic curve, and the result accords with the theory analysis. The property of above new isolation device is excellent, the seismic response of the super-structure is significantly reduced, and the fully re-centring capacity after earthquake is obtained. All the research lay foundations for further theoretical research of the re-centring device for isolation and the floor isolation techniques.