Dynamic Analysis For Non-proportional Damping Structure

Earthquake is a kind of sudden, devastating natural disasters, the damping is the main factor of seismic energy dissipation in civil engineering. The damping characteristic of the structure reflects the energy dissipation performance in vibration, the damping characteristic is an essential aspect to study the dynamic response. With the new structure shapes and new materials applied into practice, increasing of the height and the span of the structure, the more requirements of the disaster prevention and mitigation, the damping is also becoming more and more important in the engineering. Today, the structures constituted by different materials, increase more and more, especially the lower part is concrete, the upper is steel. For this type of structural system, modal damping matrix is non-diagonal matrix, the earthquake response equation is coupled on the modal damping matrix, the modal coupling of the non-proportional damping system leads to the traditional real modal analysis methods not be directly applied, the damping ratio research of non-proportional damping system has become the research hotspot. In addition, the selection of the energy dissipation damper parameters is the key to the success of energy dissipation structure, how to reasonably, fast set damper parameters is an important issue in the energy dissipation structural design. Therefore, this article targeted at non-proportional damping structure, proceeding from the practical structure problems, uses the principle of energy method to study the damping ratio of non-proportional damping structure and the problem of setting damper parameters. Through analysis and simulation of finite element program, methods of calculating the damping ratio and setting damping parameters are identified which are suitable for engineering applications and more accurate.The main research contents have three parts. First of all, on the basis of comparing several methods of calculating the damping ratio, find the damping ratio calculation method suitable for engineering applications. That is modal damping ratio method. An example is analyzed to describe the modal damping ratio method in detail, the law of the upper and lower damping ratio with structural stiffness changing is obtained. Then make Shenzhen Baoan International Airport T3 Terminal Main Concourse model as the research object, use the modal damping ratio method and the single damping ratio method to study the non-proportional damping structure, get the approximate damping ratio of the upper steel structure, the lower concrete structure and the key positions, provide reasonable proposals to the actual project. The end, make Shenzhen Baoan International Airport T3 Terminal Cross Concourse as the research object, use the viscous damping theory, determine the additional damping ratio from the perspective of response spectra and the nonlinear damping parameters from the energy point, find a reasonable, fast method to set the damping parameters, and apply this method to the practical engineering.