Compliant-Volume Tank Damping for High-Amplitude Wave Motion
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Solution Overview
Problem
Conventional motion dampers are ineffective in mitigating the high-amplitude wave-induced motions experienced by maritime structures, leading to structural degradation and performance limitations.
Innovation Solution
A compliant-volume system where containers filled with liquid and gas are used within a tank, with pressurized gas sources to modify the motion of the liquid, decoupling it from the primary structure's motion and applying a resistive force to dampen external excitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional motion dampers are used, then motion damping is provided for small amplitudes, but they are ineffective for high-amplitude wave-induced motions
Solution Approach 1:
The system uses a free surface liquid in a tank where the liquid can move dynamically in response to external excitations. The liquid's motion is modified by adjusting system parameters (such as tank geometry, liquid volume, or partition configurations) to adapt to different amplitude and frequency conditions, enabling effective damping across a wide range of motion amplitudes unlike conventional fixed-parameter dampers
Solution Approach 2:
The invention changes the physical parameters of the damping system by using a free surface liquid whose motion characteristics (amplitude, frequency, phase) can be adjusted by modifying system parameters such as tank dimensions, liquid volume, or the presence of internal structures. This allows the system to adapt to varying wave conditions and maintain effectiveness across different amplitude ranges
2Strength
If maritime structures are exposed to high-amplitude wave excitation, then structural motion occurs, but structural degradation and performance limitations result
Solution Approach 1:
The system converts the harmful high-amplitude motions into beneficial damping effects by allowing a free surface liquid to move in response to external excitations. The liquid's inertial forces and viscous dissipation convert the kinetic energy of structural motions into heat and wave energy, thereby reducing the amplitude of structural oscillations and minimizing structural degradation
Solution Approach 2:
The invention utilizes mechanical vibration principles by creating controlled liquid motions within the tank that are out of phase with the structural excitations. The liquid's sloshing and wave motions generate counteracting forces that reduce the overall structural vibrations, protecting the structure from high-amplitude damage
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 dampens high-amplitude motions, reducing structural stress and extending the lifespan of maritime structures by adjusting the frequency and phase of the liquid's motion within the tank.
Implementation Method 1
At least one gas pressurization source is in fluid communication with the remainder or gas-containing portion of at least one of the containers for pressurizing the gas therein
Implementation Method 2
the portion of the liquid contained therein and the pressure applied to the gas therein cooperate to modify movement of the liquid in the tank
Data Source
AI summary
A system and method for modifying motion of a liquid is provided. Containers are disposed within a liquid contained within a tank. Each container has an open end. Each container is disposed in the liquid such that a portion of the liquid fills a portion of each container to seal its open end. A remainder of each container is filled with a gas. At least one gas pressurization source is in fluid communication with the remainder or gas-containing portion of at least one of the containers for pressurizing the gas therein. Pressure is applied to the gas in each container. For each container, the portion of the liquid contained therein and the pressure applied to the gas therein cooperate to modify movement of the liquid in the tank.