Study On Mechanical Properties Of Shape Memory Alloys Dampers

Shape Memory Alloy (SMA) is a new kind of smart material. Because of unique and excellent character, it is developing very quickly and has a good application prospect in structure engineering. In the field of disaster prevention and reduction of civil engineering, this material is mainly used in the structural vibration control. So the study on mechanical properties of the SMA materials and the SMA dampers has important theoretical significance and application prospects.Through theory analysis, experiment study and computer simulation, this thesis studies on mechanical properties of the SMA materials and the SMA dampers. Some new conclusions and recommendations are obtained. First, the thesis describes the main characteristics of the SMA materials, the development, and the research and application status at home and abroad. The following is the mechanical performance tests of a group of austenitic super-elastic NiTi SMA wires. The effects of working temperature, loading rate, strain amplitude as well as circular number on various parameters such as equivalent secant stiffness, the largest single circular energy dissipation, equivalent damping ratio of the SMA wire under static reversed loading are analyzed. The main mechanical properties of the materials are reviewed. Against the solved characteristics of transformation super-elastic thermodynamic equation of the SMA materials in the Brinson one-dimensional constitutive model, the corresponding computer programs are programmed. Transformation super-elastic properties are simulated and analyzed. They are compared with the text results. The simulated results and the text results are identical with each other. A new kind of SMA dampers is developed. Its main mechanical properties are tested. The effects of loading trip, loading rate, working temperature as well as the number and length of SMA wires on various parameters such as equivalent secant stiffness, the largest single circular energy dissipation, equivalent damping ratio of the SMA dampers under static reversed loading are analyzed. According to the mechanical properties of the SMA dampers, the computer programs are programmed. Force-displacement hysteretic curves of the SMA dampers under static reversed loading are simulated and analyzed. They are compared with the text results. The simulated results and the text results are identical with each other. Finally, the SMA dampers are applied to the structure earthquake resistant. The control mechanism and principles are analyzed. The control effects are tested. The feasibility of its structure earthquake resistant application is discussed.