Composite Aircraft Structures with Geometric Joint Features

Solution Overview

Problem

The existing aircraft manufacturing processes for composite primary structures are labor-intensive and time-consuming, requiring complex tools and jigs for assembly, which increases lead time and costs, despite the use of composite materials for weight savings.

Innovation Solution

The use of compression moldable composite sheet molding compounds with discontinuous carbon fibers and novel geometric joint features allows for rapid assembly of aircraft primary structures by aligning and mating component parts without the need for expensive alignment tools, utilizing compression molding and adhesive bonding or mechanical fasteners.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional mechanical fastening and bonding processes are used for assembling composite aircraft structures, then structural integrity is ensured, but assembly time and labor costs increase significantly

Engineering Contradiction:

Improvestructural integrityVSAvoidassembly time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

Geometric joint features are integrated into the component parts during the molding process itself, preparing the alignment and connection interfaces in advance. This eliminates the need for separate alignment operations and reduces assembly time while maintaining structural integrity through pre-designed joint geometries

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The geometric joint features are designed to self-align and self-mate during assembly, allowing component parts to find their correct positions automatically through the complementary geometric shapes. This self-aligning mechanism eliminates the need for complex alignment tools and skilled technician intervention, reducing both time and labor costs while ensuring proper structural connection

Inventive Principle:

Principle #25Self-service

2Manufacturing precision

If complex assembly jigs and alignment tools are used to ensure precise component positioning, then manufacturing precision is improved, but capital equipment costs and device complexity increase

Engineering Contradiction:

Improvecomponent alignment precisionVSAvoidassembly equipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The geometric joint features are designed to self-align and self-mate during assembly, allowing component parts to find their correct positions automatically through the complementary geometric shapes. This self-aligning mechanism eliminates the need for complex alignment tools and skilled technician intervention, reducing both time and labor costs while ensuring proper structural connection

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention replaces expensive, complex, and reusable assembly jigs with simple, integrated geometric features that are molded into the components themselves. These geometric joint features serve as disposable alignment aids that are already present on the parts, eliminating the need for separate alignment tools and reducing capital equipment investment

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If traditional composite part fabrication using autoclave curing is used, then material properties and strength are optimized, but production lead time and capital equipment requirements increase

Engineering Contradiction:

Improvecomposite material strengthVSAvoidproduction speed

Core Design Contradiction:

StrengthVSProductivity

Solution Approach 1:

The invention changes the curing parameters from high-temperature autoclave processing to lower-temperature compression molding. This parameter change allows composite parts to be molded and cured in a single step using compression molding equipment, dramatically reducing production lead time while maintaining sufficient structural properties for the application

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention merges the molding and curing operations into a single compression molding process. Instead of separately molding and then curing composite parts in an autoclave, the geometric joint features and component parts are molded and cured simultaneously in one step, eliminating intermediate steps and reducing overall production time

Inventive Principle:

Principle #5Merging (Combining)

4Adaptability or versatility

If individual skin and internal structure pieces are mechanically fastened together, then structural assembly flexibility is maintained, but assembly process complexity and labor intensity increase

Engineering Contradiction:

Improveassembly flexibilityVSAvoidassembly ease

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The geometric joint features are designed to self-align and self-mate during assembly, allowing component parts to find their correct positions automatically through the complementary geometric shapes. This self-aligning mechanism eliminates the need for complex alignment tools and skilled technician intervention, reducing both time and labor costs while ensuring proper structural connection

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Geometric joint features are integrated into the component parts during the molding process itself, preparing the alignment and connection interfaces in advance. This eliminates the need for separate alignment operations and reduces assembly time while maintaining structural integrity through pre-designed joint geometries

Inventive Principle:

Principle #10Preliminary action

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 method significantly reduces assembly time and costs, enabling faster and more efficient production of composite aircraft primary structures while maintaining mechanical integrity to withstand 4G loading conditions during flight.

Implementation Method 1

compression molding the first 3D preform and the second 3D preform to form a first component part from the first 3D preform and a second component part from the second 3D preform

Methodology Applied

Scientific EffectCompression molding: Compression

Implementation Method 2

compression moldable composite sheet molding compounds... comprise thermoplastic and/or thermosetting polymer

Methodology Applied

Scientific EffectThermal curing: Heating

Data Source

PatentUS12084203B1Method of making composite aircraft primary structures

Publication Date: 2024.09.10 CORNERSTONE RESEARCH GROUP INC

AI summary

Methods of making a composite aircraft primary structure include selecting a compression moldable composite sheet molding compound; preparing a first and a second layup with the compression moldable composite sheet molding compound to form a first and a second 3D preform; and compression molding the first and the second 3D preforms to form a first and a second component part. Further, the first component part comprises first geometric joint features, the second component part comprises second geometric joint features, and the second geometric joint features are complementary to the first geometric joint features such that the second geometric joint features are configured to mate with the first geometric joint features. The method further includes assembling the aircraft primary structure by joining the first component part with the second component part by aligning and mating the first geometric joint features and the second geometric joint features; and securing the same.