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Scattering from a finite ribbed plate with attached oscillators
Michel Tran-Van-Nhieu1, Mai Pham Thi1, Laurent Divay1
1Thales Research and Technology, Campus Polytechnique, 1 avenue Augustin Fresnel, Palaiseau, 91767, France.
The Journal of the Acoustical Society of America
|September 6, 2018
Summary
New double layer structures effectively blur and attenuate scattering from ribbed plates. This innovative design transforms typical scattering patterns into a distinct "Christmas tree" appearance, enhancing acoustic performance.
Area of Science:
- Acoustics and Materials Science
- Wave Scattering and Attenuation
Background:
- Periodically ribbed plates exhibit Bragg and Bloch-Floquet scattering phenomena.
- Controlling acoustic scattering is crucial for applications requiring noise reduction and signal integrity.
Purpose of the Study:
- To design and analyze double layer structures for blurring and attenuating acoustic scattering.
- To investigate the effectiveness of these structures in a specific frequency bandwidth.
Main Methods:
- Development of double layer structures using stainless steel and polymer rods.
- Modeling structures as ribbed plate-spring-mass systems with oscillators.
- Utilizing analytical and finite element methods for parameter determination.
- Conducting tank tests for numerical result validation.
Main Results:
- The designed structures successfully blur and attenuate Bragg and Bloch-Floquet scattering.
- Resonance frequencies were determined through permutations of basic oscillators.
- Backscattered far-field pressure displayed a unique "Christmas tree" pattern in the (frequency, aspect angle) plane.
- Numerical models were validated against experimental tank tests.
Conclusions:
- Double layer structures offer an effective method for controlling acoustic scattering from ribbed plates.
- The observed "Christmas tree" pattern provides a new signature for analyzing backscattering.
- The validated model confirms the practical relevance of this approach for acoustic metamaterial design.
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