CFRP Intermediate Joining Part for Horizontal Stabiliser Lateral Boxes

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Solution Overview

Problem

Existing joining arrangements for the lateral boxes of an aircraft's horizontal stabiliser using intermediate parts face challenges in efficient load transmission and assembly, particularly under aerodynamic and trimming loads, and are complicated by the use of composite materials.

Innovation Solution

A joining arrangement utilizing a carbon fibre-reinforced plastic (CFRP) intermediate part with a mono-tubular or multi-tubular central box configuration, manufactured via resin transfer moulding (RTM), which includes upper and lower flaps and fitting plates for the trimming and pivoting devices, facilitating assembly and accommodating various box configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a double T-shaped intermediate part made of composite material is used to join lateral boxes, then the structural integration is improved, but the assembly complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveload transmission efficiencyVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The intermediate part is divided into a central box section and two T-shaped end sections that can be manufactured separately and then assembled. This segmentation allows each part to be optimized independently and simplifies the overall assembly process while maintaining structural integrity and load transmission efficiency.

Inventive Principle:
Principle #1Segmentation

2Strength

If intermediate parts are used to join lateral boxes of horizontal stabiliser, then load transmission between components is improved, but the number of parts and assembly steps increase

Engineering Contradiction:
Improveload transmissionVSAvoidassembly efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The central box of the intermediate part is merged with the trimming device fittings, eliminating the need for separate fitting components. This integration reduces the total number of parts and assembly steps while ensuring efficient load transmission from the lateral boxes through the intermediate part to the trimming mechanism.

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If metal intermediate parts are used for joining lateral boxes, then mechanical strength is improved, but weight and corrosion issues worsen

Engineering Contradiction:
Improvemechanical strengthVSAvoidjoint weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The intermediate part is manufactured using carbon fibre-reinforced plastic (CFRP), a composite material that provides mechanical strength comparable to or exceeding metal while significantly reducing weight. The composite material also eliminates corrosion issues associated with metal components, making it ideal for aerodynamic structures.

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If complex intermediate parts are used to accommodate trimming device fittings, then functional integration is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefunctional integrationVSAvoidsurface finish tolerance
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The central box of the intermediate part is designed to serve multiple functions: it provides structural connection between lateral boxes, houses trimming device fittings, and offers mounting points for various components. This multi-functionality is achieved through a standardized box configuration that can accommodate different fitting arrangements without requiring excessive manufacturing precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution reduces the number of parts required, ensures optimal surface finish for tolerance compliance, and allows for efficient assembly without subsequent movement of the lateral boxes, effectively addressing the challenges of load transmission and assembly complexity.

Implementation Method 1

The matrix material can be disposed in the reinforcing material by a process of resin transfer moulding (RTM)

Methodology Applied
Scientific EffectResin transfer moulding:

Data Source

PatentEP2353997B1Joining arrangement for the lateral boxes of a horizontal tail stabiliser with a tubular central box and manufacturing method for said box
Publication Date: 2019.04.24 AIRBUS OPERATIONS SL
  • EP2353997B1 patent drawingFigure 1~3
  • EP2353997B1 patent drawingFigure 4~5
  • EP2353997B1 patent drawingFigure 6~7

AI summary

Joining arrangement for the lateral boxes (11, 11') of a horizontal tail stabiliser with a central tubular box and manufacturing method for said box. The boxes (11, 11') are joined using an intermediate joining part (31) that comprises a central box (33, 63, 73), upper (35, 35') and lower (37, 37') lateral flaps, fitting plates (A) for the trimming device and fitting plates (B) for the pivoting device, the join being made with rivets between the skins (15, 15'; 17, 17') of the lateral boxes (11, 11') and said flaps (35; 35'; 37; 37'). The method for manufacturing the intermediate joining part (31) comprises steps to: a) Provide preforms suitable for forming said part (31); b) Form and cure the part (31) made from said preforms using an RTM method.