Burnthrough-Resistant Cargo Floor Using Composite Materials
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Solution Overview
Problem
Current aircraft fuselage materials, such as aluminum, are not burnthrough-resistant for more than 60 seconds, necessitating additional weight and construction costs for burnthrough-resistant insulation, which is not ideal for cargo compartments due to humidity issues and maintenance challenges.
Innovation Solution
Implementing burnthrough-resistant cargo compartment floors and wing/fuselage fairings made from high-strength carbon or glass fiber materials, along with thin mats and films in specific areas, to prevent flame penetration without the need for separate insulation mats, thereby maintaining weight and cost efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If burnthrough-resistant insulation materials are used to protect the passenger cabin, then burnthrough resistance is improved, but aircraft weight increases
Solution Approach 1:
The fuselage is divided into upper and lower halves with the burnthrough-resistant wall only in the lower half underneath the cargo compartment, while the upper half uses conventional aluminum skin. This segmentation provides targeted protection where fire risk exists from cargo fires below, while avoiding unnecessary weight in the upper passenger cabin area.
Solution Approach 2:
Burnthrough-resistant properties are applied locally only to the lower fuselage skin underneath the cargo compartment rather than uniformly across the entire fuselage. This localized application concentrates protection where it is most needed (preventing fire penetration from cargo holds) while minimizing additional weight elsewhere.
2Reliability
If burnthrough-resistant insulation materials are used, then burnthrough resistance is improved, but construction cost increases
Solution Approach 1:
The fuselage skin is segmented into two distinct zones: a lower burnthrough-resistant zone underneath the cargo compartment and an upper conventional aluminum zone. This segmentation allows manufacturers to use cost-effective conventional materials in the majority of the fuselage while applying expensive burnthrough-resistant materials only where regulatory requirements and fire risk demand it.
Solution Approach 2:
The specialized burnthrough-resistant materials and construction methods are applied locally to specific high-risk areas rather than throughout the entire aircraft. This reduces material costs, labor costs for specialized installation, and maintenance costs compared to universal application.
3Reliability
If insulation mats are arranged underneath the cargo compartment region, then burnthrough resistance is improved, but weight increases due to humidity absorption
Solution Approach 1:
The harmful function of the insulation mats (absorbing humidity and increasing weight) is eliminated by removing them from the cargo compartment region. Instead, the burnthrough protection is achieved through the burnthrough-resistant wall integrated into the fuselage structure itself, which does not suffer from humidity absorption issues.
Solution Approach 2:
The burnthrough-resistant wall acts as an intermediary structural element that provides fire protection without the detrimental humidity absorption properties of insulation mats. This wall serves as both a structural component and a fire barrier, eliminating the need for separate insulation layers that would absorb moisture.
4Ease of manufacture
If conventional aluminum structures are used, then manufacturing simplicity is maintained, but burnthrough resistance deteriorates
Solution Approach 1:
The fuselage employs different material qualities in different locations: conventional aluminum with simple manufacturing processes for the upper fuselage, and burnthrough-resistant composite materials with specialized construction for the lower fuselage underneath the cargo compartment. This local differentiation maintains manufacturing simplicity where possible while achieving required burnthrough resistance.
Solution Approach 2:
The lower fuselage skin uses composite materials combining burnthrough-resistant properties with structural requirements. These composite structures, while more complex than conventional aluminum, are applied only to specific areas, balancing the need for enhanced fire protection with manageable manufacturing complexity.
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 provides burnthrough resistance for at least four minutes without adding weight or complexity, simplifying production and maintenance while meeting safety standards, and reducing the need for additional insulation, thus enhancing aircraft performance and economy.
Implementation Method 1
carbon fibre materials or glass fibre materials may be considered for this, which materials may be applied in the form of woven-fabric structures, laminates, sandwich structures or the like
Implementation Method 2
insulation mats need to comprise special burnthrough-resistant film or foil
Data Source
AI summary
An aircraft fuselage includes at least one space arranged in the aircraft fuselage and at least one wall. The wall resists burnthrough for a period of at least four minutes from outside the aircraft fuselage towards the space, wherein the region of the aircraft fuselage underneath the space does not include burnthrough-resistant insulation. The space may be a cargo compartment of the aircraft or a passenger cabin, while the wall may be designed as a cargo compartment floor, passenger cabin floor or wing/fuselage fairing (belly fairing). The design of the aircraft fuselage results in burnthrough resistance that meets the requirements of FAR §25.856 (b) without any additional burnthrough-resistant insulation in the aircraft fuselage.