Membrane Tuned Liquid Damper for Low-Frequency Building Vibration
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Solution Overview
Problem
Current vibration damping solutions for tall buildings, such as tuned liquid dampers, are either expensive, require extensive customization, or are not adjustable, making them unsuitable for modern, slender skyscrapers with limited space and varying vibration amplitudes.
Innovation Solution
A tuned liquid damper with a membrane liquid-gas interface that includes a gas spring system with adjustable parameters, allowing for flexible membrane positioning and gas volume adjustment, which eliminates the contribution of gravity to stiffness, enabling tuning to low frequencies and efficient vibration damping in narrow buildings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard TLCD is used, then the damper is tuned to a particular frequency, but it cannot be tuned to a different frequency without major retrofit and requires large horizontal space
Solution Approach 1:
The patent applies the dynamics principle by making the damper system adjustable after installation. The liquid column length can be modified by draining and refilling, and the gas spring pre-load can be adjusted, allowing the system to adapt to different building frequencies without major structural changes. This transforms a static system into a dynamic, reconfigurable one.
Solution Approach 2:
The patent employs parameter changes by allowing modification of physical parameters such as liquid column length and gas spring pre-load. These parameter adjustments enable frequency retuning of the damper system without changing the fundamental structure, thereby improving adaptability while minimizing complexity.
2Adaptability or versatility
If a spring TLCD is used, then the stiffness can be adjusted to broader frequencies, but the adjustable stiffness can only add to gravity-induced stiffness which is too high for very tall buildings
Solution Approach 1:
The patent applies the extraction principle by removing the liquid from the traditional U-shaped tank configuration and placing it in a vertical pipe instead. This extraction of the liquid from its conventional position eliminates the gravity-induced stiffness component, allowing the gas spring to provide the only stiffness contribution. This enables tuning to lower frequencies suitable for very tall buildings.
Solution Approach 2:
The patent inverts the traditional TLCD configuration by using a vertical pipe instead of a horizontal U-shaped tank. This inversion changes the role of gravity from providing stiffness to being eliminated from the stiffness calculation, fundamentally altering the force characteristics to suit tall building applications.
3Reliability
If traditional TLDs are used, then vibration energy can be absorbed, but they require extensive customization and maintenance of large liquid tanks
Solution Approach 1:
The patent applies the universality principle by designing a damper system with standardized components (vertical pipe, gas spring, liquid column) that can be adapted to different building types and frequencies. The system maintains vibration damping effectiveness while reducing customization requirements through modular design and adjustable parameters.
4Reliability
If solid mass dampers are used, then vibration can be mitigated, but they are expensive, heavy, and reduce leasable floor space
Solution Approach 1:
The patent applies the pneumatics and hydraulics principle by using a gas spring and liquid column instead of solid mass. This fluid-based system achieves vibration mitigation through hydraulic and pneumatic mechanisms, dramatically reducing weight compared to solid mass dampers while maintaining effectiveness.
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 solution provides efficient vibration damping across a broader frequency range, is adaptable to different building heights, and reduces the obtrusiveness of the damper design, making it suitable for tall and slender structures with limited space.
Implementation Method 1
The stiffness of the gas spring depends on the enclosed volume of gas, which can be adjusted with a moveable plug after the damper is installed.
Implementation Method 2
When the water surface rises, the gas is compressed and pushes the water back down. Conversely, when the water surface drops, the gas expands and pulls the water back up.
Implementation Method 3
A standard TLCD is a U-shaped tank filled with water and sized such that the water naturally oscillates in the tank at the same frequency as the wind-induced building motion. For example, during a wind storm, the water oscillating in the tank dissipates the wind energy transferred to the building.
Implementation Method 4
A tuned liquid damper with a membrane liquid-gas interface
Data Source
AI summary
A tuned liquid damper, including a first outer housing having two ends, the first end being open to the atmosphere and the second end being connected by a conduit to a gas-filled second outer housing. The conduit may be adapted to allow gas flow between the second end and the second outer housing. The tuned liquid damper may also include first and second membranes, each attached to the inside of the first outer housing, and a sealed compartment within the first outer housing defined by the first and second membranes. The sealed compartment may be at least partially filled with a liquid, which prevents gas flow through the first outer housing from the first end to the second end.