Ballistic Membrane Fuselage for Impact Protection

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Solution Overview

Problem

Aircraft fuselages made of composite materials lack sufficient impact resistance and damage tolerance to protect against high-energy events like Propeller Blade Release (PBR) and Uncontained Engine Rotor Failure (UERF), which can lead to catastrophic damage, especially in unpressurized areas where the Auxiliary Power Unit (APU) is located.

Innovation Solution

An impact-resistant fuselage design featuring a ballistic material membrane installed inside the aircraft, mechanically linked by tensional elements that absorb impact energy through elastic deformation and resilience, allowing each membrane section to act independently and absorb energy efficiently, with tearable joints and rotating supports to prevent structural damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If composite materials are used for fuselage construction to reduce weight, then weight is reduced, but impact resistance and damage tolerance decrease

Engineering Contradiction:
Improvefuselage weightVSAvoidimpact resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies a composite protective system combining a ballistic membrane made of high-strength fabric (such as Kevlar or Spectra) with tensioning elements and structural supports. This composite structure provides impact resistance comparable to or exceeding metallic materials while maintaining the weight advantages of composite construction. The membrane material itself is a composite fabric designed for high ballistic performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs a flexible ballistic membrane as the primary protective element. This thin film structure, when tensioned and supported by the rigid fuselage framework, creates an effective impact barrier. The membrane's flexibility allows it to deform and absorb impact energy while maintaining structural integrity, resolving the contradiction between weight reduction and impact resistance.

Inventive Principle:
Principle #30Flexible shells and thin films

2Strength

If metallic shielding materials are used to protect against UERF events, then impact resistance is improved, but weight increases

Engineering Contradiction:
Improveimpact resistanceVSAvoidfuselage weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces traditional metallic shielding (aluminum or titanium) with a composite ballistic membrane system. The membrane uses high-strength-to-weight ratio materials like aramid or ultra-high-molecular-weight polyethylene fabrics, achieving comparable or superior ballistic protection against UERF events while significantly reducing weight compared to metallic alternatives.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters from dense metals to high-strength synthetic fabrics with superior specific strength (strength-to-weight ratio). This parameter change allows the protective system to maintain impact resistance while reducing weight, as the fabric materials have higher specific strength than conventional metallic shielding materials.

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If composite materials are used for fuselage construction, then weight is reduced, but damage tolerance and plasticity behavior are lost

Engineering Contradiction:
Improvefuselage weightVSAvoiddamage tolerance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent implements a dedicated ballistic membrane protective system installed within the fuselage structure before impact events occur. This pre-positioned protective layer absorbs and dissipates impact energy through controlled deformation and tearing, protecting the underlying composite fuselage structure from damage. The system provides beforehand cushioning that compensates for the inherent brittleness of composite materials.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The ballistic membrane acts as an intermediary protective layer between external impactors and the composite fuselage structure. This intermediate element absorbs the harmful impact forces through its own deformation and failure modes, preventing direct transmission of damage to the primary composite structure and thereby enhancing overall damage tolerance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 protects aircraft components by absorbing impact energy, preventing damage to critical systems like the APU, while maintaining structural integrity and minimizing weight, thus enhancing safety and ballistic performance in composite material fuselages.

Implementation Method 1

The ballistic material membrane (1) for absorbing high energy impacts... said tensional elements stress said ballistic material membrane

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3375706B1Impact resistant fuselage
Publication Date: 2022.05.18 AIRBUS OPERATIONS SL
  • EP3375706B1 patent drawingFigure 1
  • EP3375706B1 patent drawingFigure 2~3
  • EP3375706B1 patent drawingFigure 4~5

AI summary

The present invention belongs to the field of aircraft structures and aircraft protection against threat of high energy impacts, more particularly, to the field of impact resistant fuselage of an aircraft. The present invention discloses an impact resistant fuselage (6) of an aircraft, such impact resistant fuselage (6) comprising at least a ballistic material membrane (1) being located inside the aircraft fuselage (6).