The shock absorption efficiency of the newly developed neutral equilibrium mechanism in building

When a structure is hit by an earthquake, the resultant dynamic amplification threatens the safety of the structure. To counteract the seismic force and also reduce structural deformation, a control force, which requires a huge actuator, can be exerted. To avoid the use of excessively large actuators, the power capacity of the actuator needs to be reduced. To overcome these problems, the Neutral Equilibrium Mechanism (NEM) has been developed. The NEM can achieve changes in control with minimal output. The test results of the NEM confirm the following: 1. The total strength of the inner spring is equal to the total strength of the main control spring. 2. The deformation of the main control spring is zero when the angle of the linkage is zero. 3. When the angle of the linkage is +/–90 degrees, the deformation of the inner spring is zero. Considering time delay, the results of analysis show the following: 1. The time delay should be controlled to less than 0.020 seconds, and this mechanism can exert an excellent structural displacement reduction effect. 2. Comparison of the unbalanced force, the maximum output power and the maximum control power of the NEM to those of the direct control method under the same control parameters shows that when the time delay is 0.001 seconds, the unbalanced force of the NEM is only 1/230 and 1/236 of the maximum control force and the maximum output power of direct control respectively. 3. When the time delay is 0.005 seconds, the unbalanced force of the NEM is only 1/150 and also 1/150 of the maximum control and maximum output power of direct control respectively; 4. When the time delay is 0.010 seconds, the unbalanced force of this mechanism is 1/85 and 1/80 of the maximum control force and the maximum output power of direct control. The advantages of the NEM are that the control effect of a building with the NEM under a small unbalanced force and the maximum output power of a small NEM can achieve the same control effect of direct control under the same control parameters.