Research On Random Vibratiom Theory Of Structure With Superelastic Shape Memory Alloy Damper

Super-elastic shape memory alloy(referred to SMA) with large deformation recovery function, resistant to corrosion, and good fatigue resistance, is the ideal material for structure passive control. At present, the researches on SMA damper in structural vibration control are carried out under the deterministic load, but ground motion is a random process.So the research on random vibration structure with SMA will have more significance in Engineering. Based on this background, this paper mainly includes the following several aspects:1. Design the new energy-reset type SMA damper and re-centring damper SMA damper, and introduce their structure and basic theory. Based on the Graesser constitutive model, this paper introduces the mechanical models of the two SMA dampers respectively,and then mentions theirs simplified mechanical model.2. It introduces the basic theory of random process, including digital features and basic classification. It briefly introduces several common one-dimensional stationary stochastic ground motion models. Assuming that the earthquake ground motion is a stationary filtered white noise random process, it calculates the ground motion model parameters according to the latest seismic code(GB 50011-2010).3. Considering the seismic dynamic as a stationary filtered white noise random process, set up a stochastic motion equation of damping structure with stochastic equivalent linearization method, respectively according to the new energy-reset type SMA damper and re-centring damper SMA damper. Derive the random state response formula of the damping structure. Based on structure of maximum story drift beyond the first failure criterion and the reliability model of multiple degrees of freedom, study on dynamic reliability of multi-degree of freedom linear structure4. Through a six-story steel frame example, this paper calculates random vibration response and reliability of the structures with the two dampers. The results show that the dampers can effectively decrease the response of the structure effectively, and greatly improve the reliability of the power structure in four field conditions5. Through a twelve-story frame example, with the objective function that the sum of each layer displacement variance is the minimum, a better design for the position of the two SMA dampers in the structure is carried on. Using the genetic algorithm, the study concludes that under the condition of same damper quantity, the layout of SMA damper has great influence on seismic reduction effect of structure and proofs of the reliability of the genetic algorithm. It shows that the two dampers can be set on the lower layer of structure to decrease the response of the structure more effectively.