Study On The Failure Analysis Of Fluid Viscous Damper And The Influence On The Structural Performance

The Fluid Viscous Damper is a kind of energy dissipation shock absorber that can reduce structural damage induced by earthquake effectively, because of advantages such as it can assemble conveniently and flexibly, provide damp and not change the natural frequency of structure, it is used widely in realistic engineering. On the other hand, as a attachment arranged in structure, the Fluid Viscous Damper exists failure problem of energy dissipation. Cases of Oil leakage of Fluid Viscous Damper can be found, the damage of dampers were also found after the “3.11” earthquake in Japan. So to explore the failure reason of Fluid Viscous Damper, analyze the influence on structural performance, propose relative controlling strategy are beneficial to improve structural performance, and have important significance in reducing earthquake disaster and effective seismic rehabilitation.On the basis of understanding the status of Fluid Viscous Damper performance, the common phenomenon of failure existing in Fluid Viscous Damper are analyzed, and the relative restoring force model that can react degradation and failure is established to analyze the influence on structural performance under the act of earthquake, the specific research contents are as follows:(1) The restoring force models describing the action of Fluid Viscous Damper are concluded, and the respective applicable condition is comparatively analyzed. Therein, the Maxwell model and Kelvin model of Fluid Viscous Damper are the most general restoring force model. However, the failure condition of Fluid Viscous Damper are not considered in these restoring force model.(2) Common phenomenon of Fluid Viscous Damper such as oil leakage, clearance, out-limit displacement and out-limit bearing capacity is concluded, and the causes of failure of Fluid Viscous Damper are analyzed from the perspective of Fluid Viscous Damper component. According to the failure phenomenon and generated mechanism of Fluid Viscous Damper, the relative mechanical model is established, and the rationality of model is verified.(3) The Fluid Viscous Damper is analyzed and designed according to the fortification level of structure basically, but the Fluid Viscous Damper which as the fist defense line may lapse under the act of ground motion that exceed the fortification level. Based on the established out-limit mechanical model of Fluid Viscous Damper, the performance analysis of energy dissipation structure with the consideration of Fluid Viscous Damper's out-limit collapse, it can be seen that the damage of main structure will aggravate after the out-limit failure of Fluid Viscous Damper in energy dissipation structure comparing with structure without Fluid Viscous Damper.(4) The oil leakage is the failure phenomenon that can happen easily in Fluid Viscous Damper, or failure. The assembling clearance is also the inevitable phenomenon in construction. No matter the oil leakage or the existence of clearance, the influence on Fluid Viscous Damper all represent as a horizontal slipping stage. The influence of Fluid Viscous Damper considering oil leakage and clearance on the structural performance under the act of earthquake are studied, it can be found that the influence of little oil leakage and clearance that in the allowable range of error on the structural performance under small earthquake are large than that under large earthquake.(5) Basing on the performance evaluation method of existing Fluid Viscous Damper, phenomenon such as the oil leakage of damper is conducted to the energy dissipation performance evaluation, results indicate that the influence of slipping stage on the energy dissipation performance of linear damper cannot be neglected when the horizontal slipping stage is larger than the 0.2 times of design stoke.Aiming at the failure condition existed in Fluid Viscous Damper, the possible measures to prevent the failure of damper are proposed, it can be advised that the test of out-limit state should be considered when inspecting the quality of products, and the safety checking calculation after the out-limit state of damper should be conducted when designing structure; performance should be retested after certain service period of damper, then the stability of energy dissipation will be examined to prevent the damper from stopping function when the earthquake happened.