Research On The Theory Of Structural Vibration Control And Application Method Based On Shape Memory Alloys

Shape Memory Alloys (SMA) is a new kind of smart material, which has a shape memory effect. That's to say, when SMA generates plastic deformation at low temperature, the deformation can completely vanish and restore its original state at high temperature. If the restore of deformation is constrained, SMA will generate tremendous restoring force. In addition, SMA materials have characteristics of super elasticity and a rather large damp, which can dissipate major external energy.Because of advantages of SMA mentioned above, the article mainly makes use of the super elasticity and large damp properties of SMA to control the vibration of structure under the seismic responses. The key developments and creative achievements are contained in this dissertation as follows:(1) In accordance with the loading-unloading test on properties of SMA, the super elasticity of phase transition for SMA is studied, and material parameters require for finite element analysis are obtained.(2) Several types of the constitutive relation models of SMA are simply introduced; the advantages and disadvantages of them are compared in the article. The super elasticity restoring force model adopted in the ANSYS program is analyzed, which provides bases for analysis on the mechanical behavior of SMA by means of ANSYS.(3) Based on the theory of vibration control, in the light of the property of shear deformation of structure, the time-history response analysis of structure is performed for a model of the 6-story steel frame under the excitation of earthquake; the control effectiveness by SMA passive cables is researched, the corresponding mechanism and law of control is also explored. The results demonstrate that the vibration control with prestrained SMA. cables diagonally set at stories can not only effectively mitigate structural response to earthquake, but also it is easy for detailing, of high adaptability and thus enjoy an extensive application.(4) A new passive control method is put forward, in which the control instrument of SMA is installed near the inflection point of frame columns to perform a passive control over the structural response to earthquake, the corresponding principle and law of control is investigated, and the effectiveness of control is then verified. The results indicate that the control instrument of SMA set near the inflection point of columns can also realize a valid control over the seismic response of structure, and this instrument in application can be selected according to actual cases.