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A passive tuned mass damper (TMD) fabricated using the Reid damping, referred to as the Reid-TMD, is proposed. First, the characteristics of the Reid damping model are introduced, followed by the presentation of a passive variable friction damper to achieve this model. Next, the steady-state response of single-degree-of-freedom structures with the Reid-TMD under a harmonic load is solved by the harmonic balance method (HBM), together with an error analysis of the results. Subsequently, the optimization and control effect of the Reid-TMD damping system are analyzed and compared with the traditional viscous damping TMD. The results show that under the action of a harmonic load or seismic load, the vibration suppression effect of the Reid-TMD with the same mass ratio is essentially equivalent to the traditional viscous damping TMD. In addition, the damping control effect increases with the increase in mass ratio. When the mass ratio is less than 0.05, the energy dissipation coefficient is less than 0.5 and the frequency ratio is less than 0.95. For parameters within this range, the steady-state response of the seismic reduction structure with the Reid-TMD is solved by the HBM. If the parameters of the Reid-TMD are outside this range, the error of the HBM becomes large, and recourse should be changed to general numerical methods. The optimum parameters of the Reid-TMD are determined through an optimization analysis for the mass ratio in the range of 0.005–0.1. While using the Reid-TMD for the vibration absorption design, the optimum parameters can be acquired directly by using the established tables. Because the passive variable friction damper has good durability and economy, the application of the Reid-TMD is beneficial to shock absorption technology.

Under harmonic load and random stationary white noise load, the existing fitting formulas are not suitable for calculating the optimal parameters of large mass ratio tuned mass dampers (TMDs). For this reason, the optimal parameters of large mass ratio TMDs are determined by numerical optimisation methods, and a revised fitting formula is proposed herein based on a curve fitting technique. Finally, the dynamic time history analysis method is used to study the control effect of large mass ratio TMDs. The results show that when the mass ratio is large, the error between the existing fitting formula and the actual optimal value is quite large, and the revised fitting formula is applicable to the parameter design of the traditional small mass ratio and large mass ratio (≤1) TMDs. When the ratio of local base soil predominant frequency to structure vibration frequency is greater than 4, the optimal parameters of a TMD under white noise excitation can be calculated according to the revised fitting formula, and the remaining conditions should be determined by numerical optimisation. In addition, a large mass ratio TMD reduces the dynamic response of the main structure effectively compared with a small mass ratio TMD and reduces the relative displacement between the TMD and main structure.

No abstract

Under earthquake action, the reinforced concrete structure at the edge of the CAP1400 nuclear power plant foundation slab will be uplifted. In order to determine the seismic performance of this structure, a 1 : 12 scale shaking table test model was fabricated using gypsum as simulated concrete in order to meet scaled design requirements. By testing this model, the seismic response of the structure with consideration of the foundation uplift was obtained. Numerical analyses of the test model and the prototype structure were conducted to gain a better understanding of the structural seismic performance. When subjected to earthquakes, the foundation slab of the nuclear power plant experiences a slight degree of uplift but remains in the elastic stage due to the weight of the structure above, which provides an antioverturning moment. The numerical simulation is in general agreement with the test results, suggesting numerical simulations could be accurately employed in place of physical tests. The superstructure displacement response was found not to affect the safety of adjacent structures, and the seismic performance of the structure was shown to meet the relevant design requirements, demonstrating that this approach to modelling can serve as a design basis for the CAP1400 nuclear power demonstration project.