Aircraft Leading Edge Multilayer Panels for Bird Strike Resistance

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Solution Overview

Problem

Existing aircraft leading edge structures face challenges in optimizing rigidity to withstand bird strikes and aerodynamic loads while minimizing damage and weight, as conventional designs often rely on thick aluminum or hybrid materials that are heavy and inefficient in energy absorption.

Innovation Solution

A leading edge structure composed of multilayer panels with a metal foil outer layer, a fibreglass intermediate layer, and a honeycomb metal layer, where the layers are securely fixed with adhesives and arranged to absorb impact energy through bridging and crushing, respectively, to enhance rigidity and reduce weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If thick aluminum or hybrid materials are used for the leading edge structure, then the structure can withstand bird strikes and aerodynamic loads, but the weight of the wing or empennage increases

Engineering Contradiction:
Improveimpact resistanceVSAvoidweight of leading edge structure
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent employs a composite structure consisting of a metal foil layer (aluminum or aluminum alloy, 0.2-0.5mm thick), a fibreglass intermediate layer (0.1-0.5mm or up to 1mm thick), and a honeycomb metal layer (0.6-2.5cm thick). This composite configuration achieves superior specific strength and energy absorption capability compared to conventional solid aluminum structures, thereby reducing weight while maintaining or enhancing impact resistance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different layers of the leading edge structure. The metal foil provides a smooth aerodynamic surface and initial impact resistance, the fibreglass layer contributes to elasto-plastic deformation energy absorption through bridging, and the honeycomb layer provides structural rigidity and crushable energy absorption. This local differentiation of material functions optimizes the overall performance-to-weight ratio.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the leading edge structure is made more rigid to withstand aerodynamic loads, then structural integrity is maintained, but the ability to absorb impact energy through deformation is reduced

Engineering Contradiction:
Improvestructural rigidityVSAvoidenergy absorption capacity
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent divides the leading edge structure into distinct functional layers: a thin metal foil outer layer for aerodynamic smoothness and initial impact resistance, a fibreglass intermediate layer for elasto-plastic energy absorption, and a honeycomb inner layer for structural rigidity and crushable energy absorption. This segmentation allows each layer to specialize in specific functions, achieving both rigidity and energy absorption capacity simultaneously.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent incorporates a honeycomb metal layer with a porous cellular structure (0.6-2.5cm thick) that provides high structural rigidity relative to its weight while maintaining the capability to crush and absorb impact energy. The honeycomb geometry creates a controlled collapse mechanism that dissipates energy during bird strikes while preserving overall structural integrity.

Inventive Principle:
Principle #31Porous materials

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 achieves a 30% weight savings with comparable deformation resistance to Glare technology, effectively limiting damage propagation and reducing overall weight while maintaining structural integrity.

Implementation Method 1

Fibre-glass contributes in an important way to absorbing a substantial fraction of the elasto-plastic deformation energy due to impact; this effect is called 'bridging' in the field of the materials applied to aircrafts.

Methodology Applied
Scientific EffectBridging:

Implementation Method 2

a third honeycomb metal layer (23) having a thickness of between about 0.6 cm and about 2.5 cm, comprising walls locally perpendicular to the surface on which the layer lies

Methodology Applied
Scientific EffectCrushing:

Data Source

PatentEP2196309B1Leading edge for aircraft wings and empennages
Publication Date: 2011.11.09 ALENIA AERMACCHI
  • EP2196309B1 patent drawingFigure 1~6
  • EP2196309B1 patent drawingFigure 3~4

AI summary

The leading edge structure (10) comprises two or more multilayer panels (20) at least partially overlapping and suitably curved with at least partially congruent concavities. Each multilayer panel includes at least the following three layers: - a first layer (21) consisting of a metal foil, - a second intermediate layer (22) of fibre-glass securely fixed to the first layer (21), and - a third metal honeycomb layer (23) securely fixed to the second layer (22).