Voided Elastomeric Noise Attenuator for Side Wall Panel
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Solution Overview
Problem
Existing noise attenuators, particularly those used in the aircraft and automotive industries, are ineffective in reducing vibratory-induced noise, especially at mid and high frequency ranges, and require larger and heavier units to achieve better performance.
Innovation Solution
A voided elastomeric noise attenuator with a rigid core element and elastomeric bushing, featuring radially extended end plates and circumferentially spaced voids, which are bonded to both the core and a bracket, to reduce noise transmission from a supporting frame to a side wall panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional elastomeric attenuators are used to reduce noise transmission, then noise attenuation is achieved, but the size and weight of the attenuator units must be increased to improve performance
Solution Approach 1:
The elastomeric bushing is segmented by introducing circumferentially spaced voids that divide the material into separate sections. This segmentation allows the attenuator to achieve superior noise attenuation performance while maintaining a compact size and reduced weight, as the voids create multiple attenuation paths without requiring increased overall dimensions.
Solution Approach 2:
The elastomeric bushing incorporates voids to create a porous structure that enhances noise attenuation capabilities. The porous configuration allows vibratory energy to be dissipated more effectively through multiple interfaces and pathways, achieving 15 dB improvement across mid and high frequency ranges without increasing the attenuator's external dimensions or weight.
2Object-affected harmful factors
If conventional elastomeric attenuators are used, then some noise attenuation is achieved, but performance at mid and high frequency ranges is insufficient
Solution Approach 1:
The elastomeric bushing is segmented by introducing circumferferentially spaced voids that divide the material into separate sections. This segmentation allows the attenuator to achieve superior noise attenuation performance while maintaining a compact size and reduced weight, as the voids create multiple attenuation paths without requiring increased overall dimensions.
Solution Approach 2:
The elastomeric bushing incorporates voids to create a porous structure that enhances noise attenuation capabilities. The porous configuration allows vibratory energy to be dissipated more effectively through multiple interfaces and pathways, achieving 15 dB improvement across mid and high frequency ranges without increasing the attenuator's external dimensions or weight.
3Object-affected harmful factors
If larger and heavier attenuator units are used to improve noise attenuation, then noise reduction performance increases, but the weight and size of the attenuator units increase
Solution Approach 1:
The elastomeric bushing is segmented by introducing circumferferentially spaced voids that divide the material into separate sections. This segmentation allows the attenuator to achieve superior noise attenuation performance while maintaining a compact size and reduced weight, as the voids create multiple attenuation paths without requiring increased overall dimensions.
Solution Approach 2:
The elastomeric bushing incorporates voids to create a porous structure that enhances noise attenuation capabilities. The porous configuration allows vibratory energy to be dissipated more effectively through multiple interfaces and pathways, achieving 15 dB improvement across mid and high frequency ranges without increasing the attenuator's external dimensions or weight.
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 solution provides a 15 dB improvement in noise attenuation across a wide frequency range (100 Hz to 10,000 Hz) without increasing the size or weight of the attenuator units, effectively addressing the limitations of existing technologies.
Implementation Method 1
An elastomeric bushing is bonded to both the core element and a portion of the bracket such that the bushing fills the space between the end plates
Implementation Method 2
A pair of opposed voids are sometimes placed longitudinally in the bushing to soften the spring rate of the bushing along the reaction axis of the system
Data Source
AI summary
A noise attenuator for attaching a side wall panel to a frame that is exposed to vibratory loads and which includes a rigid core having a sleeve with two radially disposed end plates. A bracket encircles a portion of said sleeve between the end plates and is in non-contiguous relationship with the core. An elastomeric bushing is bonded to a portion of the bracket and the core with the exception of the outer faces of the end plates, which remain exposed. Voids are passed through the rear plate and extend axially between the bracket and the sleeve some length into the sleeve. Due to the geometry of the unit, the non-voided sections of the bushing are loaded in either a combination of tension and shear or compression and shear when the core is connected to a vibrating frame and the bracket is connected to a side wall panel.