Twisted Composite Wires for Curved Part Undulation Control

Solution Overview

Problem

Composite parts with curved zones in the aerospace and automotive industries face mechanical performance issues due to undulations caused by differences in filament lengths along the width of wires, leading to non-homogeneous deposits and potential weaknesses under stress.

Innovation Solution

A method involving the twisting of reinforcing wires to compensate for length differences across their width, ensuring a consistent trajectory and minimizing undulations, thereby enhancing the homogeneity and mechanical performance of the composite parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If wires are deposited along curved trajectories on a deposit surface, then the part geometry can be formed, but undulations occur due to different filament lengths at extreme trajectories, resulting in non-homogeneous deposits

Engineering Contradiction:

Improvecurved trajectoryVSAvoiddeposit homogeneity

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The wire is pre-twisted before deposition to introduce a preliminary helical configuration. This preliminary action compensates for the length differences that will occur during curved deposition, allowing the filaments to accommodate the varying path lengths without creating undulations in the final deposit.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The twist parameter of the wire is modified to create a helical configuration. By changing the geometric parameter (twist) of the wire before deposition, the system compensates for the length variations inherent in curved trajectories, resulting in a homogeneous deposit despite the curved path.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If untwisted wires are used in curved zones, then the manufacturing process is simpler, but mechanical performance deteriorates due to undulations and filament length inconsistencies

Engineering Contradiction:

Improvewire processingVSAvoidmechanical performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The wire is pre-twisted before deposition to introduce a preliminary helical configuration. This preliminary action compensates for the length differences that will occur during curved deposition, allowing the filaments to accommodate the varying path lengths without creating undulations in the final deposit.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The twist parameter of the wire is modified to create a helical configuration. By changing the geometric parameter (twist) of the wire before deposition, the system compensates for the length variations inherent in curved trajectories, resulting in a homogeneous deposit despite the curved path.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2152498B1Method for making composite parts having at least one curved area

Publication Date: 2019.05.29 HEXCEL REINFORCEMENTS SAS

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AI summary

The invention relates to a method for making a composite part including an assembly of superimposed webs of reinforcement threads imbedded at least partially in a polymer matrix, said part including at least one curved area and the method comprising steps of draping or stacking plies of a composite material, characterized in that, in at least one area adjacent to a curved area, at least one draping or stacking step is carried out with a ply of composite material, that comprises a web, or twisted thread web, including at least one twisted reinforcement thread in order to at least compensate the length differences of the extreme paths of the thread on either side of the width as measured in a direction parallel to the surface of the web; the invention also relates to the composite materials thus obtained.