Composite Aircraft Frame with Integral Recesses

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Solution Overview

Problem

Existing frame manufacturing methods for aircraft, particularly those using fibre-reinforced plastic composite materials, require costly and time-consuming milling processes to create recesses for longitudinal beams, which compromises the structural integrity and increases weight due to the disruption of the flange, leading to reduced mechanical stability and increased production effort.

Innovation Solution

The frame is produced integrally from fibre-reinforced plastic composite materials with recesses formed as integral pockets, eliminating the need for milling and maintaining a continuous flange for enhanced stability, using methods like liquid moulding, RTM, or PRE-PREG, and incorporating interwoven fibres for increased stiffness and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If recesses for longitudinal beams are created by milling in fibre-reinforced plastic frames, then the frame can accommodate longitudinal beams, but the flange is disrupted and mechanical stability is reduced

Engineering Contradiction:

Improverecess creation methodVSAvoidmechanical stability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The frame is divided into multiple frame elements, each with integrated recesses formed as pockets during moulding. This segmentation allows each element to be independently manufactured with built-in beam accommodation features, eliminating the need for post-manufacturing milling operations that would compromise structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The frame elements are produced from fibre-reinforced plastic composite materials using liquid moulding methods. The composite material structure allows recesses to be formed as integral pockets during the moulding process itself, maintaining continuous flange geometry and preserving mechanical stability while accommodating longitudinal beams.

Inventive Principle:

Principle #40Composite materials

2Ease of manufacture

If multiple retaining anchors are used to form recesses, then milling is avoided, but the number of parts and assembly complexity increases

Engineering Contradiction:

Improverecess creation methodVSAvoidnumber of parts

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The recesses are merged into the frame element structure itself, formed as integral pockets during the moulding process. This consolidation eliminates the need for separate retaining anchors or other auxiliary components, reducing part count and assembly complexity while maintaining the ability to accommodate longitudinal beams.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The recesses are prepared in advance as integral pockets during the frame element manufacturing process, before assembly. This preliminary formation of recesses during moulding eliminates the need for additional components or post-assembly operations, simplifying both manufacturing and assembly processes.

Inventive Principle:

Principle #10Preliminary action

3Weight of moving object

If fibre-reinforced plastic materials are used, then weight is reduced, but production complexity increases compared to traditional metals

Engineering Contradiction:

Improveframe weightVSAvoidproduction process

Core Design Contradiction:

Weight of moving objectVSEase of manufacture

Solution Approach 1:

The recesses are formed as integral pockets during the initial moulding process, before assembly or finishing operations. This preliminary action during manufacturing eliminates the need for subsequent milling operations, reducing overall production complexity despite using advanced fibre-reinforced plastic materials.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The manufacturing process parameters are optimized for liquid moulding of fibre-reinforced plastics, with the mould design incorporating features that allow direct formation of recesses as pockets. This parameter optimization simplifies production by integrating multiple features into a single manufacturing step, offsetting the complexity of working with composite materials.

Inventive Principle:

Principle #35Parameter changes

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 approach results in a lightweight, stable frame with reduced production costs and increased mechanical stability, avoiding the drawbacks of traditional methods by maintaining the flange integrity and eliminating the need for multiple parts and rivets, while meeting high stress capacity requirements.

Implementation Method 1

The frame elements are produced from fibre-reinforced plastic, with the recesses being formed as integral pockets of the frame elements

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Implementation Method 2

using methods like liquid moulding, RTM, or PRE-PREG

Methodology Applied

Scientific EffectLiquid moulding:

Implementation Method 3

using methods like liquid moulding, RTM, or PRE-PREG

Methodology Applied

Scientific EffectRTM (Resin Transfer Moulding):

Implementation Method 4

incorporating interwoven fibres for increased stiffness and reduced weight

Methodology Applied

Scientific EffectInterwoven fibres:

Data Source

PatentUS9387918B2Frame and method for producing such a frame

Publication Date: 2016.07.12 FACC

AI summary

A frame for reinforcing a hull of a craft, particularly an aircraft, contains at least one frame element that is shaped in accordance with the curvature of the hull and has recesses at a side facing the hull for the passage of longitudinal beams of the craft. Each frame element is integrally formed from a fiber-reinforced plastic composite material and the recesses are configured as integral cut-outs of each frame element.