Floating Base Isolation with Tuned Gas Chamber for Seismic Vibration
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Solution Overview
Problem
Existing floating structures with air chambers are unable to effectively suppress the excitation of vibrations caused by seismic waves, leading to significant vibrations in the floating structure and mounted devices during earthquakes.
Innovation Solution
A floating-type base isolation system is designed with a liquid storage portion, a floating structure, and a gas accommodation space that adjusts its volume based on the natural frequency of the system responding to seismic waves, ensuring this frequency is lower than that of the floating structure and mounted devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an air chamber is provided to the floating structure, then the floating structure can support the mounted device, but the excitation of the floating structure and mounted device cannot always be suppressed during earthquakes
Solution Approach 1:
The patent changes the physical parameters of the fluid system by introducing a gas-liquid two-phase mixture and controlling the gas volume ratio. By adjusting the proportion of gas (which has lower density and different compressibility compared to liquid alone), the natural frequency of the fluid system is modified to fall within 0.5-2 Hz, thereby reducing seismic excitation while maintaining support capability
Solution Approach 2:
The patent creates a composite fluid system combining gas and liquid phases. This two-phase fluid mixture exhibits different mechanical properties compared to pure liquid, specifically achieving a natural frequency range of 0.5-2 Hz that effectively reduces earthquake-induced excitation while preserving the buoyancy needed to support the floating structure and mounted device
2Speed
If the volume of gas accommodation space is increased, then the natural frequency of the system decreases, but the volume elastic modulus of the fluid decreases
Solution Approach 1:
The patent deliberately adjusts the gas volume ratio parameter to achieve optimal values. By controlling the amount of gas in the two-phase fluid system, the natural frequency is reduced to 0.5-2 Hz while the volume elastic modulus is maintained at appropriate levels through proper gas-liquid ratio selection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces the excitation of the floating structure and mounted devices caused by earthquakes, minimizing vibrations and enhancing stability by aligning the natural frequency of the system with seismic wave frequencies.
Implementation Method 1
As the volume of the gas accommodation space increases, a volume elastic modulus of the fluid may decrease, and the natural frequency of the system that responds to the seismic wave may decrease
Data Source
AI summary
A floating-type base isolation system includes: a liquid storage portion storing liquid; a floating structure floated and arranged on the liquid; and a gas accommodation space formed at a position in contact with the liquid and accommodating gas. A volume of the gas accommodation space is set based on a natural frequency of a system that responds to a seismic wave propagating in fluid including the liquid and the gas.