LIVE Piston Port Design for Compact Vibration Isolation
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Solution Overview
Problem
Current vibration isolation systems in aircraft, particularly helicopters, face challenges in achieving compact designs while maintaining effective vibration attenuation, as they require significant resources and often necessitate radical redesigns to improve performance.
Innovation Solution
The introduction of a liquid inertia vibration elimination (LIVE) system with a nonlinear tuning port allows for a greater tuning mass to travel beyond the piston's height, utilizing a fluid path through a central axis, and an adjustable orifice to dynamically tune the system, enabling efficient vibration cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vibration isolation systems are used in aircraft, then vibration attenuation is achieved, but the system size and weight become excessive
Solution Approach 1:
The patent employs a hydraulic inertial vibration isolator that uses fluid (hydraulic fluid) instead of traditional solid mass elements. The fluid is contained in a flexible bladder that can expand and contract, allowing the tuning mass to change volume dynamically. This hydraulic approach enables effective vibration isolation with significantly reduced weight compared to traditional solid mass isolators, as the fluid provides the necessary inertial properties while being much lighter than equivalent solid materials.
Solution Approach 2:
The patent implements variable tuning capability by allowing the tuning mass volume to change. The flexible bladder can expand to increase the tuning mass volume when vibration attenuation is needed, and contract to reduce it when less attenuation is required. This dynamic parameter change enables the system to adapt to different vibration conditions while maintaining compact size and reduced weight, resolving the contradiction between effective attenuation and system weight.
2Weight of stationary object
If vibration isolation systems are designed to be compact, then weight and size are reduced, but vibration attenuation performance deteriorates
Solution Approach 1:
The patent employs dynamic tuning capability where the tuning mass volume can change in response to vibration conditions. The flexible bladder allows the tuning mass to expand when vibration attenuation is required and contract when not needed. This dynamic adjustment enables a compact device to achieve effective vibration attenuation performance by optimizing the tuning mass volume in real-time, rather than requiring a permanently large fixed mass.
Solution Approach 2:
The hydraulic system with flexible bladder provides a compact yet effective vibration isolation solution. The fluid-filled bladder can expand to provide the necessary tuning mass for vibration attenuation while maintaining a compact overall device size. When the bladder contracts, the device size is minimized. This hydraulic approach allows the system to achieve effective attenuation performance in a compact package that would be impossible with traditional solid mass isolators.
3Reliability
If the tuning mass volume is increased to improve vibration isolation, then the device size increases
Solution Approach 1:
The patent implements a dynamically adjustable tuning mass volume using a flexible bladder. The bladder can expand to increase the tuning mass volume when effective vibration isolation is required, and contract to reduce the device volume when less isolation is needed or when space is constrained. This dynamic volume adjustment allows the system to achieve effective vibration isolation only when necessary, maintaining compact size during normal operation.
Solution Approach 2:
The system changes the tuning mass volume parameter dynamically based on vibration conditions. The flexible bladder allows the tuning mass to expand its volume to provide adequate vibration isolation effectiveness, and contract to minimize device volume. This parameter change capability resolves the contradiction by allowing large tuning mass volume only when required for effective isolation, rather than maintaining large volume continuously.
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
This compact design effectively isolates vibrations by leveraging inertial forces, providing improved vibration attenuation with reduced size and weight, allowing for incremental performance enhancements without complete system redesigns.
Implementation Method 1
A vibration isolator utilizes inertial forces (m{"umlaut over (x)"}) to cancel elastic forces (kx). Halwes '607 discloses a vibration isolator, in which a dense, low-viscosity fluid is used as the "tuning" mass to counterbalance, or cancel, oscillating forces transmitted through the isolator.
Implementation Method 2
Halwes '607, it was recognized that the inertial characteristics of a dense, low-viscosity fluid, combined with a hydraulic advantage resulting from a piston arrangement, could harness the out-of-phase acceleration to generate counter-balancing forces to attenuate or cancel vibration.
Data Source
AI summary
A piston for use in a liquid inertia vibration elimination (“LIVE”) system. The piston includes a port that extends from a first end of the piston to an opposite second end of the piston, wherein a length of the port is longer than a length between the first and second ends of the piston.