Research On Shock Absorption Performance And Parameter Optimization Of Parallel Accelerated Oscillator Dampers

In this paper,a damper-parallel acceleration oscillator damper?PAOD?is proposed to improve the safety of a beam bridge whose displacement of the main beam is constrained by a fixed pier under seismic loads.PAOD can be installed on the main beam,and the kinetic energy of the main beam is amplified and transmitted to the damper through the gear rack system of the transmission device,so PAOD can absorb and dissipate more kinetic energy.On the basis of PAOD,this paper proposes an elastic parallel acceleration oscillator damper?EPAOD?.The installation method and working principle of EPAOD are the same as that of PAOD.The difference is that EPAOD is used to improve the safety of the beam bridge with elastic connection between the main beam and the pier under the action of seismic load,which effectively expands the use of PAOD.The article uses the Lagrange principle and the D'Alembert principle to derive the equations of motion of PAOD and EPAOD,and solve the equations of motion by the Newmark?method,and then compares with the results of the finite element displacement coupling simulation to demonstrate the correctness of the equation of motion.After obtaining the motion equations of PAOD and EPAOD,this paper conducts basic research and parameter optimization of PAOD and EPAOD through formula derivation and frequency response function.Parameter optimization is based on damped and undamped structures,respectively,and the effects of various parameters on the vibration reduction effect are obtained through H₂ and_?optimization,and then the actual bridge simulation is performed with the results of damped H₂optimization to demonstrate the PAOD and EPAOD for beam bridges vibration reduction effect under seismic loads.After studying PAOD and EPAOD,it was found that under certain circumstances,multiple PAODs can be converted into a single PAOD,and EPAOD has similar characteristics.The results of parameter optimization show that when the damper achieves the optimal frequency ratio,optimal damping ratio and appropriate transmission ratio,the key factor affecting the vibration reduction effect of PAOD and EPAOD is the stiffness ratio between the secondary structure and the main structure,and the mass ratio of the damper has little effect on the optimal vibration reduction effect.The simulation results of the real bridge show that PAOD and EPAOD have a good shock absorption effect on the beam bridge,and the shock absorption effect has good stability.The PAOD proposed in this paper is mainly used for beam bridges with fixed piers constraining the displacement of the main beam.EPAOD is proposed on the basis of PAOD.EPAOD is mainly used for beam bridges with elastic connections between the main beam and the pier.The PAOD and EPAOD dampers amplify the shock absorption effect through the transmission device,which has a significant shock absorption effect when the mass ratio is small,and has the advantages of low cost and simple installation.