Rotorcraft Mount Isolating Component Vibrations via Elastomer
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Solution Overview
Problem
Aircraft components such as rotors, engines, and accessory gear boxes produce vibrations that cause noise and structural integrity issues, as these vibrations are transmitted to the airframe, exacerbating existing vibrations and leading to discomfort for operators and passengers, and potentially harming the aircraft's mechanical integrity.
Innovation Solution
Incorporating an elastomer between rigid members, such as a bracket and a structural support member, to isolate vibrations from aircraft components at one frequency from reaching the airframe, while the airframe vibrates at a different frequency, thereby attenuating noise and reducing the transmission of vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid members are directly coupled to transmit vibrations, then structural strength and stability are improved, but vibration transmission and noise increase
Solution Approach 1:
An elastomer is introduced as an intermediary element between the rigid bracket and the rigid structural support member. The elastomer serves as a vibration isolation element that attenuates vibrations at a first frequency while allowing the structure to respond to vibrations at a second frequency (N-per-rev), thereby reducing noise and vibration transmission without compromising structural integrity
Solution Approach 2:
The elastomer's material properties and geometric parameters are specifically designed to create frequency-dependent behavior. The isolation element is configured to be effective at attenuating vibrations at a first frequency while maintaining structural responsiveness at a second frequency, achieving frequency-selective vibration isolation
2Object-generated harmful factors
If vibration isolation elements are added, then noise and vibration are reduced, but device complexity increases
Solution Approach 1:
The elastomer serves multiple functions simultaneously: it acts as a vibration isolation element to attenuate noise, a structural connector to join rigid members, and a frequency-selective filter to differentiate between vibration frequencies. This multi-functionality reduces the need for additional separate components
Solution Approach 2:
The mount structure combines rigid materials (bracket and structural support member) with a flexible elastomeric material to create a composite vibration isolation system. This composite approach enables the structure to simultaneously provide structural strength and vibration attenuation without requiring complex additional components
3Object-generated harmful factors
If isolation elements are placed between rigid members, then vibration transmission is reduced, but weight increases
Solution Approach 1:
The elastomer is implemented as a flexible isolation element that can be positioned between the rigid bracket and structural support member. This flexible element provides vibration attenuation without requiring heavy mass, leveraging the elastomer's inherent damping properties and frequency-selective behavior
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 elastomer effectively reduces noise and vibration transmission, enhancing the structural integrity and comfort of aircraft operations by isolating vibrations at their source, without adding significant weight or bulk, and ensuring the solution does not amplify the N-per-rev frequency vibrations.
Implementation Method 1
The elastomer is configured to attenuate acoustic noise caused by the vibrations at the first frequency by isolating the vibrations at the first frequency from reaching the airframe
Implementation Method 2
an elastomer is located between two or more rigid members
Implementation Method 3
The structural support member is configured to transfer a weight of the component of the aircraft to an airframe of the aircraft
Implementation Method 4
The first rigid member is configured to transfer a weight of a component of the rotorcraft to the airframe
Data Source
AI summary
One example of a mount for a rotorcraft comprises a structural support member, a bracket, and an elastomer. The bracket is configured to attach to a component of the rotorcraft. The component of the rotorcraft produces vibrations at a first frequency. The structural support member configured to transfer a weight of the component of a rotorcraft to an airframe of the rotorcraft. A rotor system of the aircraft vibrates the airframe of the rotorcraft at a second frequency. The elastomer is located between a structural support member and a bracket. The elastomer is configured to attenuate noise caused by the vibrations at the first frequency by isolating the vibrations at the first frequency from reaching the airframe of the rotorcraft while the airframe vibrates at the second frequency.