Corrugated Core Acoustic Panel for Low-Frequency Noise
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Solution Overview
Problem
Aircraft engines with higher bypass ratios and larger fan diameters generate low-frequency noise, which existing acoustic panels struggle to attenuate due to space constraints and increased complexity and cost when trying to tune resonating chambers for these frequencies.
Innovation Solution
The acoustic panel design incorporates a cellular core with corrugated structures and multiple resonance chambers between perforated and non-perforated skins, allowing for multi-degree of freedom noise attenuation with reduced panel assembly time, complexity, and cost, using a configuration that includes primary and secondary corrugated structures to extend sound wave trajectories and enhance noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the core thickness is increased to tune resonating chambers for low frequency noise, then noise attenuation performance is improved, but space constraints are violated and panel size increases
Solution Approach 1:
The patent implements nested corrugated structures where inner corrugations are positioned within outer corrugations, creating multiple resonating chambers in a compact configuration. This nesting allows the panel to achieve low-frequency noise attenuation typically requiring greater thickness while maintaining a compact overall profile that fits within space constraints
Solution Approach 2:
The patent transitions from a single-layer honeycomb structure to a multi-layer corrugated configuration with chambers extending in multiple directions. By creating resonating chambers that propagate in different spatial dimensions rather than simply increasing thickness in one direction, the panel achieves enhanced low-frequency attenuation while controlling overall panel dimensions
2Object-affected harmful factors
If septums are added within resonating chambers to provide multiple degrees of freedom, then noise attenuation across multiple frequencies is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the core into multiple discrete corrugated layers, each containing resonating chambers tuned to different frequencies. This segmentation into functional layers provides multi-degree of freedom noise attenuation across multiple frequency ranges while maintaining manufacturing simplicity through standardized modular construction of each layer
Solution Approach 2:
The corrugated structure serves multiple functions simultaneously: it provides structural support for the panel, creates resonating chambers for noise attenuation, and defines chamber geometries through the corrugation patterns. This multi-functionality eliminates the need for separate septum components while achieving multi-frequency attenuation capabilities
3Ease of manufacture
If traditional honeycomb core structure is used, then manufacturing is simple, but noise attenuation effectiveness for low frequency noise is insufficient
Solution Approach 1:
The patent employs a composite core structure combining multiple corrugated layers with different chamber configurations and orientations. This composite approach maintains manufacturing simplicity by using repetitive corrugation forming processes while achieving superior noise attenuation effectiveness through the synergistic interaction of multiple chamber types resonating at different 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
This design effectively attenuates low-frequency noise and other select frequencies while maintaining or reducing space, complexity, and cost, providing a more efficient solution for noise reduction in aircraft propulsion systems.
Implementation Method 1
The core includes a plurality of chambers, a first corrugated structure and a second corrugated structure. The chambers includes a first chamber. The first chamber extends from the perforated first skin, through the first corrugated structure and the second corrugated structure, to the second skin.
Data Source
AI summary
An acoustic panel is provided that includes a perforated first skin, a second skin and a core. The core is between and connected to the perforated first skin and the second skin. The core includes a plurality of chambers, a first corrugated structure and a second corrugated structure. The chambers includes a first chamber. The first chamber extends from the perforated first skin, through the first corrugated structure and the second corrugated structure, to the second skin.