Metallic-Composite Joint Using Segmented Titanium Fastener

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Solution Overview

Problem

Current methods for manufacturing metallic-composite joints are time-consuming and expensive, particularly when using aluminum alloy, which is not compatible with composite materials, and require the same material for the metallic spike and component, limiting compatibility and increasing costs.

Innovation Solution

A method involving a metallic component with a hole and a metallic fastener with a shaped head and tail portion, where the tail extends through the composite component's fibre layers, allowing for different materials and improved compatibility, with the fastener made of titanium alloy and the component of aluminum alloy, and using shaping techniques to enhance attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminum alloy is used for the metallic component, then cost is reduced, but compatibility with composite materials deteriorates

Engineering Contradiction:
Improvecompatibility with composite materialsVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The metallic component is segmented into two distinct parts: the main component body (made of cost-effective aluminum alloy) and the fastener (made of titanium alloy for composite compatibility). This segmentation allows each part to be optimized independently - the component body for cost efficiency and the fastener for compatibility with composite materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different material properties are applied to different locations of the assembly. The aluminum alloy is used for the main component where cost efficiency is prioritized, while titanium alloy is used locally at the fastener location where compatibility with composite materials is critical. This local differentiation resolves the contradiction between cost and compatibility.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the metallic spike is made of the same material as the metallic component, then manufacturing simplicity is improved, but material compatibility with composite components deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidmaterial compatibility
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The fastener is segmented from the main component, allowing independent material selection. The fastener is made of titanium alloy specifically for its compatibility with composite materials, while the main component can be made of aluminum alloy. This segmentation eliminates the constraint that previously required identical materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The titanium alloy fastener acts as an intermediary element between the aluminum alloy component and the composite material. It mediates the interface where material compatibility is critical, preventing direct contact between aluminum alloy and composite materials while maintaining structural integrity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If heating to very high temperature is used to make the surface liquid, then spike formation is improved, but energy consumption and process complexity increase

Engineering Contradiction:
Improvespike formation capabilityVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The thermal process (heating to very high temperature to make surface liquid) is replaced with a mechanical process (direct forming of the fastener). The fastener is formed with its final shape including the head portion and tail portion before installation, eliminating the need for high-temperature heating and liquid surface formation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fastener is preliminarily formed with its complete geometry (head portion, tail portion, and any necessary features) before installation. This preliminary shaping eliminates the need for subsequent high-temperature processing during assembly, reducing energy consumption and simplifying the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3034280B1A metallic-composite joint
Publication Date: 2020.02.12 AIRBUS OPERATIONS LTD
  • EP3034280B1 patent drawingFigure 1a~1e
  • EP3034280B1 patent drawingFigure 2a~3c
  • EP3034280B1 patent drawingFigure 4a~4d

AI summary

Method of manufacturing a metallic-composite joint comprising a metallic component (110) having one hole (111) in a surface thereof, and a metallic fastener (20) having a head portion (22) for attaching to the metallic component (110) and a tail portion (23 ) for attaching to a composite component, comprising the steps of positioning the metallic fastener (20 )such that the head portion of the metallic fastener is retained in the hole, and the tail portion of the metallic fastener extends out of the hole, arranging layered fibres of an uncured composite component on the surface of the metallic component such that the tail portion extends through a gap between adjacent fibres in each fibre layer, and curing the composite component.