Theoretic And Experimental Study Of A New Type Of Shape Memory Alloy Damper

Structural vibration energy dissipation is a kind of structural control technology, which employs energy-dissipation devices installed in proper locations of the structure to dissipate part of structural vibration energy under earthquake and wind so as to reduce the structural vibration response. Shape memory alloy (SMA) is an ideal material to dissipate vibration energy because of its properties of shape memory effect (SME), super elasticity effect and damping effect. So the shape memory alloy damper, which is based on these properties, is a good kind of energy-dissipation device. It can reduce the seismic and wind-vibration response of the engineering structures effectively. So the studies on the shape memory alloy damper are valuable in theory and practice. The current situations of researches and applications of shape memory alloy damper are briefly reviewed in this thesis firstly. Then a new type of damper device based on shape memory alloy (SMA) wires is developed for structural control implementation. Based on this new type damper, some new engineering applications in construction buildings and long-span bridges with this damper are proposed. Then the theoretic and experimental study of this new type of damper technology for structural vibration energy-dissipation is performed to verify the vibration energy dissipation ability of the new type of SMA damper. Finally based on the experimental results, finite element method is adopted to simulate the earthquake response of the frame model, controlled uncontrolled by SMA damper. The main contents and results are as follows.Based on the properties of the SMA, a new type of damper device based on shape memory alloy (SMA) wires is developed for structural control implementation. This kind of SMA damper can supply tension damping, compression damping, torsion damping and bending damping at the same time.Based on this new type damper, some new engineering applications in construction buildings and long-span bridges with this damper are proposed. It can be used in many kinds of structures and installed easily and have several advantages that other dampers don't have.The theoretic study on such damper is performed, including the research on fundamental damping principle of the damper and mechanics damping analysis of such developed reduced-scale damper. The various affecting factors to the working performance of SMA damper are discussed. The formula of the output damping force and displacement is gotten when the damper is tensed or compressed, rotated and bent. The dynamical experiment of such reduced-scale damper is performed to verify the damping analysis results and the vibration energy dissipation ability of the new type of SMA damper. It is found that the experimental results are in good agreement with the theoretic values. From the experimental restoring force curve, the damping coefficient and stiffness of damper are calculated. Based on these parameters of the damper, finite element method is adopted to simulate the earthquake response of the frame model, controlled and uncontrolled by SMA dampers. The numerical results illustrate that the earthquake response displacement of the frame model is reduced greatly and its vibration decay rate is increased effectively after the developed SMA dampers are fixed in it. Such type of SMA damper is a good device to dissipate energy and to reduce the vibration of the structures.