Reliability Analysis Of Metallic Dampers

Energy dissipation technologies now have become one of the most efficient methods in structure design, metallic dampers which have stable energy dissipating performance and remarkable economical efficiency are one of those technologies and have been widely used in actual structures. There has been very limited researches about the reliability of dampers for structural use so far. However, dampers play a very important role in structures’ seismic performance. Therefore, a relatively comprehensive research about the reliability of the metallic dampers is conducted in this study, the main work and findings of this study are as follows:(1) A series of experiments about both the material and dampers are conducted in this study, taking LY160 low yield point steel as example. First, increment step experiments about LY160 are conducted in order to research the material’s strain strengthening effect, basing on which proper time-history analysis model is established. Second, a series of high strain low cycle fatigue experiments are conducted so as to gain the low cycle fatigue life model of this material for the reliability calculation of the dampers. Third, low cycle fatigue experiments with an interval about the material are conducted for the purpose to research the connection of the interval and material’s fatigue life, similarly, low cycle fatigue experiments with an interval about the dampers are also conducted to research the relationship of the interval and damper’s fatigue life, which can provide basis for fatigue life correction when we take aftershock into consideration.(2) Traditional rain-flow method is mainly used in fields like astronautics and mechanical engineering, in which they focus on high cycle fatigue, therefore this method doesn’t take the strain strengthening effect of metals into consideration. In this study, a correctional rain-flow method is proposed and so is the corresponding Matlab program. Low cycle fatigue is taken as the failure criterion of metallic dampers. The symmetric latin hyper-cube sampling method is adopted to get samples of earthquake wave, then the samples of earthquake wave are input into the finite element software for elastic-plastic analysis to gain the deformation time history of the dampers in structures. The correctional rain-flow method is used to calculate and analyze the time history records. If the Miner linear cumulative damage is larger than 1, the damper is considered to have failed. Finally, the failure probability is calculated by calculating the results of all the sampled earthquake waves.(3) An example of a six-floor RC frame structure with shear panel dampers is given in order to explain the calculating method proposed in this study. Earthquake waves containing both main shock and after shock is chosen to calculate the failure probability of the metallic dampers.