Fuel Bladder Mass Attenuation via Flexible Gas Bag

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Solution Overview

Problem

Existing protective assemblies for aircraft fuel containers and bladders, particularly those made of reinforced vulcanized rubber, face challenges in effectively attenuating hydrodynamic pressures and reducing fire risk during crashes, while also needing to minimize weight and protect adjacent support structures.

Innovation Solution

A protective assembly comprising a gas bag with a pressurized inert gas, such as nitrogen or argon, that extends along the walls of the fuel container, equipped with pressure release valves to manage hydrodynamic forces and extinguish sparks, constructed from non-permeable materials like Kapton or Mylar, to attenuate forces and prevent fires.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid-cell ballistic foam material is used to surround the fuel container, then fire protection and energy attenuation are improved, but aircraft weight increases significantly

Engineering Contradiction:

Improvefire protectionVSAvoidaircraft weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces rigid-cell ballistic foam with a flexible bladder constructed of thin-walled material that can deform during impact events. This flexible membrane provides fire containment and energy attenuation through deformation rather than rigid structural resistance, dramatically reducing weight while maintaining protective functions.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the physical state and mechanical properties of the protective material from rigid and elastic to flexible and deformable. The bladder is designed to undergo large deformations and volume changes during impact, converting kinetic energy through material deformation rather than rigid foam crushing, thereby achieving protection with minimal weight addition.

Inventive Principle:

Principle #35Parameter changes

2Force

If rigid-cell ballistic foam material is used to surround the fuel container, then energy attenuation is improved, but aircraft weight increases significantly

Engineering Contradiction:

Improveenergy attenuationVSAvoidaircraft weight

Core Design Contradiction:

ForceVSWeight of moving object

Solution Approach 1:

The flexible bladder provides energy attenuation through controlled deformation and volume reduction during impact events. The thin-walled flexible structure absorbs kinetic energy through material deformation and geometric collapse rather than rigid foam crushing, achieving effective force attenuation with minimal weight penalty.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The bladder is designed to dynamically respond to impact forces by deforming, compressing, and changing volume during crash events. This dynamic behavior allows the flexible membrane to absorb and dissipate energy through time-varying deformation rather than static rigid structure, providing effective protection with lightweight construction.

Inventive Principle:

Principle #15Dynamics

3Force

If the fuel container wall is flexible, then the gas bag can effectively attenuate hydrodynamic pressures, but the container is more susceptible to damage from kinetic energy of fuel during crash

Engineering Contradiction:

Improvehydrodynamic pressure attenuationVSAvoidcontainer resistance to kinetic energy

Core Design Contradiction:

ForceVSStrength

Solution Approach 1:

The flexible bladder is pre-installed within the fuel container to provide cushioning before impact events occur. During crash, the bladder deforms and compresses to absorb hydrodynamic pressures from fuel kinetic energy, protecting the container walls and support structures from damage through预先 positioned energy absorption.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 gas bag effectively attenuates hydrodynamic pressures, reduces the risk of fire, and minimizes weight addition to the aircraft, providing enhanced protection for both the fuel container and adjacent support structures during crashes and ballistic events.

Implementation Method 1

attenuate forces or hydrodynamic pressures generated as a result of kinetic energy of the fuel contained within the fuel container or bladder

Methodology Applied

Scientific EffectHydrodynamic pressure:

Implementation Method 2

A protective assembly comprising a gas bag with a pressurized inert gas... to manage hydrodynamic forces

Methodology Applied

Scientific EffectGas compression: Compression

Implementation Method 3

equipped with pressure release valves to manage hydrodynamic forces and extinguish sparks

Methodology Applied

Scientific EffectPressure release: Depressurisation

Implementation Method 4

constructed from non-permeable materials like Kapton or Mylar, to attenuate forces and prevent fires

Methodology Applied

Scientific EffectInert atmosphere:

Data Source

PatentUS10518894B2Fuel bladder mass attenuation system

Publication Date: 2019.12.31 THE BOEING CO

AI summary

A protective assembly includes a gas bag and a fuel container which includes a first wall. The fuel container is positioned within an aircraft and the gas bag extends along the first wall of the fuel container. A method for assembling a protective assembly includes the step of positioning a gas bag within an aircraft such that the gas bag extends along a first wall of a fuel container.