Composite Acoustic Liner Perforation Strategy
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Solution Overview
Problem
Existing acoustic panels in gas turbine engines are heavy, increasing aircraft weight and fuel consumption, while lighter composite materials raise manufacturing costs and complexity.
Innovation Solution
A two-stage polymerization process for manufacturing composite acoustic panels, using a permeable face-layer, impermeable backing sheet, and sound absorbing layer, with perforations created after the second polymerization stage to minimize weight and costs, and optimize sound attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional acoustic panels are used, then noise attenuation is achieved, but weight increases significantly
Solution Approach 1:
The patent applies composite materials by combining a permeable face-layer made of composite material with a sound-absorbing core layer. This composite structure achieves noise attenuation functionality while significantly reducing weight compared to traditional solid panels, directly resolving the contradiction between noise attenuation and weight reduction
2Weight of moving object
If composite materials are used to reduce weight, then panel weight decreases, but manufacturing cost and complexity increase significantly
Solution Approach 1:
The patent segments the acoustic panel into distinct functional layers: a permeable face-layer and a sound-absorbing core layer. This segmentation allows each layer to be manufactured separately using optimized processes, then assembled together. The face-layer can be made from composite materials at lower cost, while the core layer uses conventional sound-absorbing materials, thereby reducing overall manufacturing complexity and cost while maintaining weight reduction benefits
3Use of energy by moving object
If acoustic panels are made lighter, then fuel economy improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by making the face-layer permeable with specific local properties (controlled porosity and permeability) rather than requiring the entire panel to have uniform high precision. The sound-absorbing core layer compensates for any variations, allowing the overall structure to achieve weight reduction for fuel economy while maintaining adequate manufacturing precision through the distributed functional properties of different layers
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 method reduces manufacturing costs and weight of acoustic panels, improving fuel efficiency and noise attenuation while maintaining precise geometric tolerances and aerodynamic performance.
Implementation Method 1
polymerising said laminate to form a substantially continuous face-layer at a first polymerisation pressure of approximately atmospheric pressure or at a pressure greater than atmospheric pressure
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3
AI summary
The invention relates to a method of manufacturing a composite acoustic panel employed in an inlet passage of a gas turbine engine (1). The acoustic panel comprises a permeable face-layer (8), an impermeable backing sheet (9) and a sound absorbing layer (10) disposed therebetween. The method comprises a double polymerisation process for the face- layer and the remainder of the acoustic panel and finally a perforation step to perforate the face -layer according to a pre - determined perforation distribution (11.1, 11.2, 11.3, 11.4, 11.5).