エネルギ回生機構の多段化による制震オイルダンパの効率向上に関する研究

抄録

 We presented a novel semi-active oil damper that developed to break through the limitations of existing oil dampers by introducing a unique energy recovery system in our previous paper. This energy recovery damper is equipped with an auxiliary oil tank outside the main cylinder, and the oil flows between the cylinder and the tank are controlled by changing valves. Existing oil dampers, including variable damping types, always change the vibration energy to heat. However, the energy recovery damper recovers the vibration energy as strain energy of the oil in the tank and reuses it at an optimum timing to improve control efficiency.

 This paper describes a possibility of enhancing the energy dissipation capacity of the above-mentioned energy recovery damper by introducing a multistep energy recovery system. In order to investigate the energy recovery process in detail, it found that there is an unrecoverable energy with a single oil tank. By adding extra oil tanks, this unrecoverable energy can be used to improve the damper’s performance. First, we examined using double energy recovery systems. Fig. 6 shows the basic configuration and mechanical model of the oil damper with double energy recovery systems and Fig. 8 shows the operating process. As shown in Fig. 10, double step energy recovery operation can improve the energy dissipation capacity. The effects of tank stiffness ratio and tank usage sequence are also quantitatively evaluated. Next, in order to generalize the multistep effect, the energy dissipation capacity using any n tanks is quantitatively provided. Eq.(23) is the dissipated energy per cycle in steady state. Based on Eq.(23), the relationships between the energy dissipation capacity and the tank stiffness ratio in steady state are shown in Fig. 11 and Fig. 12. From these figures, the effect of a total volume of oil tanks and number of energy recovery system can be observed. The energy dissipation capacity using multistep control for harmonic excitations or earthquakes are examined through a theoretical approach and numerical response analysis.

 Following results are obtained by the theoretical and numerical studies.

 1. There is unrecoverable energy in the operation process of the energy recovery damper. The most important point of improvement is how much unrecoverable energy can be reduced.

 2. Usage of the additional tanks and control valves can reduce the unrecoverable energy and the energy dissipation capacity can be improved.

 3. The theoretical study based on the mechanical models showed quantitatively the relationship between the total volume of the oil tanks and the multistep energy recovery system. Regardless of the total tank stiffness ratio that is defined by the total volume of the oil tanks, the greater the number of the oil tanks, the greater the energy dissipation capacity.

 4. In the multistep energy recovery process, the order of the oil tanks to be used is better last-in first-out than first-in first-out and uniform tank stiffness ratios are better than non-uniform tank stiffness ratios.

 5. The enhancing effect of the energy dissipation capacity by the multistep control confirm for harmonic excitations and earthquakes.