Acoustic Panel With Structural Septum For Engine Noise Attenuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
There is a challenge in attaching acoustic sandwich panels to aircraft engine systems while maintaining acoustic properties, structural capabilities, and packaging considerations, particularly for modern high-bypass-ratio turbofan engines that generate increasing low-frequency noise.
Innovation Solution
The solution involves using acoustic panels with a core structure sandwiched between permeable skins and septums, where the panels are configured for attachment using mounts and fasteners like flanges and blind fasteners, allowing for efficient attachment while maintaining acoustic resonance and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If acoustic sandwich panels use larger cavities to attenuate low-frequency noise, then acoustic attenuation performance is improved, but attachment difficulty and packaging constraints worsen
Solution Approach 1:
The acoustic panel is divided into multiple layers with alternating permeable and impermeable skins, creating a multi-layer sandwich structure. This segmentation allows the panel to achieve effective low-frequency noise attenuation through distributed cavity resonance while maintaining a compact overall size that simplifies attachment to engine components.
Solution Approach 2:
The patent employs a nested structure where multiple acoustic panels can be stacked and attached together using common rails and fasteners. The modular design allows panels to be nested within the engine nacelle structure, achieving the required acoustic attenuation through cumulative effect while maintaining packaging efficiency and simplifying installation.
2Object-affected harmful factors
If acoustic sandwich panels use larger cavities for low-frequency attenuation, then acoustic performance is improved, but panel package size increases
Solution Approach 1:
The patent transitions from using large single-dimension cavities to creating resonance chambers through multi-layer stacking in the third dimension. By alternating permeable and impermeable skins across multiple layers, the system achieves equivalent acoustic performance to large cavities while compressing the volume requirement through vertical layering rather than horizontal expansion.
Solution Approach 2:
The acoustic panel uses a composite sandwich structure combining permeable and impermeable materials in alternating layers. This composite construction creates distributed resonance chambers that achieve low-frequency noise attenuation equivalent to larger monolithic cavities, while the composite nature allows for optimized material usage and reduced overall panel volume.
3Object-affected harmful factors
If acoustic sandwich panels use larger cavities for low-frequency attenuation, then acoustic performance is improved, but weight increases
Solution Approach 1:
The acoustic panel is segmented into multiple thin layers with alternating permeable and impermeable skins, creating distributed resonance chambers. This segmentation achieves effective low-frequency noise attenuation through cumulative acoustic impedance across multiple interfaces, while each individual layer remains lightweight, reducing the total weight compared to a single large-cavity structure.
Solution Approach 2:
The patent employs composite material construction with alternating permeable and impermeable layers, optimizing the weight-to-acoustic-performance ratio. The composite structure distributes the acoustic attenuation function across multiple material interfaces, achieving low-frequency noise control with reduced material mass compared to traditional single-material large-cavity designs.
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 configuration effectively attenuates low-frequency noise while ensuring secure attachment to engine components, meeting both acoustic and structural requirements within weight and size constraints.
Implementation Method 1
The panels typically comprise two skin surfaces which sandwich between them at least one layer of a core material... This enables the cells of the core to act like individual Helmholtz resonators that attenuate a certain tone or tones of noise generated by the engine.
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A sound attenuation device (300) includes an acoustic panel (302) having a first end (306) and a second end (308) spaced from the first end (306). The first end (306) is configured for attachment to a first mount (310) and the second end (308) is configured for attachment to a second mount (314). The acoustic panel (302) comprises a permeable skin (332) and a septum (334), the septum (334) having a length (320) extending between the first end (306) and the second end (308).