Wire Rope Isolator Damper for Multi-Frequency Airframe Vibration
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Solution Overview
Problem
Current aircraft dampers are inadequate in effectively managing vibrations across multiple frequencies, particularly in rotorcraft and vertical take-off and landing aircraft, where vibrations from rotor blades can cause significant discomfort and structural stress.
Innovation Solution
A damper assembly utilizing wire rope isolators with specific stiffness, compression/shear, and shape characteristics to isolate vibrations in two or more frequencies, attached to the airframe via fasteners, providing frequency isolation and reducing vibration levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dampers are used to reduce vibration at a single frequency, then vibration control at that specific frequency is improved, but the damper cannot effectively manage vibrations across multiple frequencies
Solution Approach 1:
The damper is divided into separate functional components: a mass element and a wire rope isolator system. The mass element targets specific vibration frequencies while the wire rope isolators handle isolation across multiple frequencies through their nonlinear mechanical properties, allowing the system to address both single-frequency control and multi-frequency adaptability
Solution Approach 2:
The wire rope isolators utilize changes in stiffness parameters under different loading conditions. The isolators exhibit nonlinear behavior where their effective stiffness changes with amplitude and frequency of vibration, enabling them to adaptively control vibrations across multiple frequencies rather than being fixed to a single frequency
2Reliability
If a mass is directly attached to the airframe for vibration damping, then the damping effect is maximized, but the mass cannot provide frequency isolation
Solution Approach 1:
The wire rope isolators serve as intermediary elements between the mass and the airframe. These isolators provide a compliant connection that enables frequency isolation while still allowing the mass to exert damping forces on the airframe, thus mediating between the conflicting requirements of direct attachment for damping and isolation for frequency selectivity
3Strength
If wire rope isolators with high stiffness are used to support the mass, then the mass can be effectively supported, but vibration isolation across multiple frequencies is reduced
Solution Approach 1:
The wire rope isolators exhibit dynamic characteristics where their effective stiffness varies with the amplitude and frequency of vibration. Under static or low-amplitude conditions, they provide sufficient support strength, while under high-amplitude multi-frequency vibrations, their nonlinear behavior enables effective isolation by reducing their effective stiffness at isolation frequencies
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 damper assembly effectively reduces vibration levels by isolating the mass from the airframe, using wire rope isolators with tailored properties to manage vibrations across multiple frequencies, enhancing the comfort and structural integrity of aircraft.
Implementation Method 1
one or more wire rope isolators having a first and a second portion, wherein the mass is attached to the one or more wire rope isolators and the mass is isolated from the airframe by the one or more wire rope isolators
Data Source
AI summary
The present invention includes a damper assembly, method and kit to provide dampening to an airframe comprising: a mass to dampen the vibration of the airframe; one or more wire rope isolators having a first and a second portion, wherein the mass is attached to the one or more wire rope isolators and the mass is isolated from the airframe by the one or more wire rope isolators; and a first fastener and a second fastener, wherein the first fasteners attaches to the first portion of the wire rope isolator to the mass, and the second fastener attaches the second portion of the wire rope isolator to the airframe to dampen vibration of the airframe.