Switchable Fluid Path Vibration Isolator for Aircraft
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Solution Overview
Problem
Existing vibration isolation systems in aircraft, particularly rotary wing aircraft, face challenges in minimizing size, weight, and frequency adaptability without radical redesign, as they are constrained by the use of dense, toxic fluids and fixed frequency settings.
Innovation Solution
The introduction of a switchable fluid path liquid inertia vibration eliminator that employs a low-viscosity, non-corrosive fluid and a valve system to dynamically adjust the fluid path, allowing for active tuning of vibration isolation frequencies by altering the fluid flow path configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense fluid (mercury) is used as the tuning mass in a vibration isolator, then the isolation frequency can be effectively controlled, but the device becomes toxic and corrosive
Solution Approach 1:
The patent replaces the toxic but effective mercury with a non-toxic alternative fluid that can be easily replaced or refilled. This allows the system to maintain its vibration isolation function while eliminating the harmful effects of mercury, treating the fluid as a consumable component rather than a permanent fixture
Solution Approach 2:
The patent acknowledges that while mercury provides excellent vibration isolation, its toxicity is a harmful side effect. By substituting it with a safe fluid and designing a system that can compensate for the alternative fluid's properties, the invention converts the harmful aspect into a benefit by making the system safe for civilian and commercial aircraft applications
2Adaptability or versatility
If the vibration isolator is designed with a fixed frequency setting, then the device structure is simple, but it cannot adapt to different vibration modes
Solution Approach 1:
The patent introduces a movable piston that can be repositioned within the fluid chamber to change the volume of the compressible gas. This dynamic adjustment mechanism allows the isolator to adapt to different vibration frequencies by modifying the gas spring constant, transforming a static system into a dynamically adjustable one
Solution Approach 2:
The patent changes the physical parameters of the isolation system by adjusting the gas volume and pressure through piston movement. This allows the same physical device to operate at different frequencies by modifying the elastic properties of the gas spring, rather than requiring multiple fixed-frequency isolators
3Volume of moving object
If the isolator volume is reduced to minimize aircraft weight, then the device becomes more compact, but the isolation effectiveness decreases
Solution Approach 1:
The patent uses a compressible gas (pneumatic element) instead of a mechanical spring to provide the elastic restoring force. This allows for a more compact design because the gas can be compressed into a smaller volume while still providing the necessary force, and the same device can be adjusted to provide different force levels by changing the gas pressure
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
Enables flexible frequency isolation by selectively changing the isolation frequency based on valve positions, improving vibration reduction efficiency and adaptability without the need for extensive redesign, using a non-toxic and efficient fluid.
Implementation Method 1
a dense, low-viscosity fluid is used as the 'tuning' mass to counterbalance, or cancel, oscillating forces transmitted through the isolator. This isolator employs the principle that the acceleration of an oscillating mass is 180° out of phase with its displacement
Implementation Method 2
an elastomeric element stores and releases energy to provide vibration isolation
Data Source
AI summary
A vibration isolator having a housing defining a fluid chamber, piston assembly, tuning passage, and a switchable fluid path assembly for changing the isolation frequency of the vibration isolator. The piston assembly is resiliently disposed within the housing. A vibration tuning fluid is allowed to flow within the housing. Actuation of a valve in the switchable fluid path assembly selectively controls fluid flow within the fluid path of the switchable fluid path assembly.