Composite Structural Element Junctions Using Extractable Resilient Inserts

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Solution Overview

Problem

Conventional methods for manufacturing composite material structural elements, such as wing spars and beams, face issues with geometrical imprecision in junction areas due to filler production processes, leading to increased rejects, repairs, and difficulties in non-destructive testing, as well as unnecessary weight and material costs.

Innovation Solution

The method involves using resilient inserts in nodal junction areas between the web and flanges of structural elements, which are extracted after curing, eliminating the need for conventional fillers and allowing for improved geometric quality and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fillers are used in junction areas, then the cavity is filled and support function is provided, but geometrical imprecision and defects occur

Engineering Contradiction:
Improvegeometrical precision of junction areasVSAvoidquality of junction areas
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention extracts the filler material from the final structure by using extractable cores that are removed after curing. This eliminates the geometrical imprecision and defects associated with conventional permanent fillers while maintaining their temporary support function during manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The extractable cores are placed in position before curing to provide the necessary support and shape during the manufacturing process. Their temporary presence enables precise geometric formation, and they are subsequently removed to eliminate the associated defects.

Inventive Principle:
Principle #10Preliminary action

2Strength

If conventional fillers are used, then support function is provided during curing, but weight and material costs increase

Engineering Contradiction:
Improvesupport function in junction areasVSAvoidweight of structural elements
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The support function is provided temporarily by extractable cores during curing, then the cores are removed. This eliminates the permanent weight penalty of conventional fillers while maintaining the necessary support function during the critical curing phase.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The extractable cores are discarded after serving their temporary support purpose. This allows the structure to achieve its final lightweight state while still benefiting from the support function during manufacturing, and the cores can potentially be recovered and reused.

Inventive Principle:
Principle #34Discarding and recovering

3Manufacturing precision

If conventional fillers are used, then junction areas are filled, but non-destructive testing becomes difficult

Engineering Contradiction:
Improvefilling of junction areasVSAvoidinspection of radial areas
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

By removing the extractable cores after curing, the obstruction to ultrasonic inspection is eliminated. The junction areas are properly formed during curing when the cores are present, but the cores are subsequently extracted to allow clear inspection pathways.

Inventive Principle:
Principle #2Taking out (Extraction)

4Weight of moving object

If extractable inserts are used, then weight and material costs are reduced, but inserts must be extracted after curing

Engineering Contradiction:
Improveweight of structural elementsVSAvoidextraction process complexity
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The invention accepts the extraction step as necessary to achieve the weight benefits. The extractable cores are designed to be removable after curing, enabling the final structure to achieve its target lightweight state.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The extraction process is integrated into the manufacturing workflow. The cores are discarded or recovered systematically after serving their temporary purpose, and this step is accepted as part of the overall manufacturing process to achieve the weight reduction goal.

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP2998090B1Methods for manufacturing elongated structural elements of composite material
Publication Date: 2020.09.30 LEONARDO SPA
  • EP2998090B1 patent drawingFigure 1~3
  • EP2998090B1 patent drawingFigure 4~6
  • EP2998090B1 patent drawingFigure 7~9

AI summary

Resilient inserts (20) are inserted into the nodal junction areas (14) between the web (13) and the flanges (11, 12) of an elongated structural element (10) of composite material. After the curing step, the inserts (20) are extracted from the cured structural element, leaving cavities (29) extending longitudinally through the nodal areas (14).