Metal-Composite Leading Edge for APU Protection
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Solution Overview
Problem
Leading edges of noise attenuation devices in auxiliary power units are vulnerable to damage from foreign object debris, ice formation, and rain erosion, which can lead to operational inefficiencies and damage, particularly in composite materials.
Innovation Solution
A protective leading edge assembly comprising an outer strike shell with a metallic layer and a composite layer, along with a foam core, which provides protection against FOD and rain erosion while incorporating heating elements to prevent ice formation, and embedded sensors for monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a composite leading edge cover is used, then weight is reduced and manufacturing is easier, but resistance to rain erosion and FOD damage deteriorates
Solution Approach 1:
The leading edge cover employs a composite construction combining a composite material layer (such as fiber-reinforced plastic) with a metallic layer (such as aluminum or stainless steel). This composite structure leverages the weight advantages and manufacturing ease of composite materials while the metallic layer provides enhanced resistance to rain erosion and foreign object debris damage, thus resolving the contradiction between weight reduction and damage resistance.
Solution Approach 2:
The solution implements a layered structure where one material layer is positioned within or alongside another material layer. The composite layer forms the base structure for weight reduction, while a metallic protective layer is applied over it to provide erosion and impact resistance. This nested arrangement allows both materials to contribute their respective advantages simultaneously.
2Productivity
If the leading edge is exposed, then air inlet efficiency is maintained, but vulnerability to ice formation and FOD strikes increases
Solution Approach 1:
A thin protective shell or cover is applied over the leading edge structure. This shell is designed to be aerodynamically smooth to maintain air inlet efficiency while providing a protective barrier against ice accumulation and foreign object debris strikes. The shell may incorporate heating elements or be designed with specific aerodynamic features to prevent ice formation while preserving airflow characteristics.
3Object-affected harmful factors
If a protective shield is added to the leading edge, then resistance to FOD and rain erosion is improved, but device complexity increases
Solution Approach 1:
The protective function is merged with the structural function of the leading edge cover itself. Rather than adding a separate protective shield as an additional component, the protective layer is integrated into the cover structure through composite material construction. This combining approach provides FOD and rain erosion resistance while minimizing increases in device complexity, as the protective and structural functions are unified in a single integrated assembly.
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 effectively shields the leading edge from damage, maintains operational efficiency by preventing ice formation, and reduces the risk of motor shutdown, offering a cost-effective and durable solution for noise attenuation devices.
Implementation Method 1
the metallic layer can protect the composite layer against FOD damage, rain erosion, or other damage
Implementation Method 2
can allow the composite layer to provide strength to the metallic layer
Implementation Method 3
the outer strike shell can protect the core from FOD damage, rain erosion, or other damage
Implementation Method 4
The core can be made of a foam material, such as a rigid fire-retardant foam
Implementation Method 5
The heating elements can transfer heat to the outer strike shell, which can reduce the chance of ice formation
Implementation Method 6
incorporating heating elements to prevent ice formation
Data Source
AI summary
Various components and methods related to a leading edge assembly are disclosed. The leading edge assembly can include an outer strike shell and a foam core. The foam core can be located inside the outer strike shell. The leading edge assembly can include a heating element with a plurality of sensors and wires. A method of manufacturing a leading edge assembly can include forming a composite layer, applying a metallic layer to the composite layer, installing an electronic device, and inserting a foam core into a cavity bounded by the composite layer and/or the electronic device.