Optimal Design And Placement Of Negative Stiffness Device Using Genetic Algorithm

Given its reliability,easy maintenance and independence of external energy and signal,passive control is the most widely used control technique among many structural control strategies.However,current passive control strategies also have some drawbacks,such as residual deformation,maintenance after earthquake,damper durability and additional loads to the structure.Negative stiffness device(NSD)can reduce structure stiffness so that will be effective on acceleration and shear control.Design and displacement of Negative Stiffness Device was optimized using genetic algorithms and Benchmark.Time-history analysis of displacement and acceleration was done.Rail generatrix equation of Negative Stiffness Device was optimized using genetic algorithms.The initial population size was 20,the binary length was 20.The NSD track equation was Optimized using gatbx GA toolbox and Benchmark model.In the case an eight-story steel braced frame structure with independent foundation under the NSD control was known,the Time-history analysis of displacement and acceleration was did.The results showed that,displacement decreasing amplitude was 24% through optimizing the amplitude A and frequency ω of the track equation.The displacement response control of structure installed the optimized NSD under the earthquake was greatly increased to insure safety of the structure.Displacement of Negative Stiffness Device was optimized using genetic algorithms.The initial population size was 20,the binary length was 20.The optimal strategy and model was the same with optimal design.The results showed that,displacement decreasing amplitude was 20% through optimizing the displacement of NSD.The Time-history analysis of displacement and acceleration was done to draw a conclusion that the acceleration was the unchanged and the displacement was apparently reduced after optimizing.In conclusion,Negative stiffness device(NSD)is effective on acceleration.After the optimal design and displacement of negative stiffness device,the performance of NSD in displacement control is enhanced by about 20%.When the acceleration control effect of the NSD device is unchanged,the optimal NSD apparently enhanced the control effect of the displacement response.