Repairing 3D Woven Composite Parts Using Segmented Fiber Preforms

Solution Overview

Problem

Composite material parts with three-dimensional fiber reinforcement are difficult to repair without compromising their non-delaminable nature, as existing methods risk delamination when using pre-impregnated fiber patches.

Innovation Solution

A method involving the creation of recessed sections, grooves, and orifices in the damaged area, followed by the placement and impregnation of three-dimensionally woven fiber preforms to form a filling part that mechanically attaches to the composite material, ensuring high resistance to delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If pre-impregnated fiber patches are used to repair composite material parts, then the repair process is simple and easy to perform, but the repaired area is prone to delamination which compromises the non-delaminable nature of three-dimensional woven composite materials

Engineering Contradiction:

Improveease of repairVSAvoidresistance to delamination

Core Design Contradiction:

Ease of repairVSReliability

Solution Approach 1:

The repair method segments the fiber reinforcement into multiple layers (first layer, second layer, third layer) with different orientations. The first layer has fibers oriented perpendicular to the surface at the damaged area, the second layer has fibers parallel to the surface, and the third layer has fibers perpendicular to the surface. This segmentation allows each layer to serve specific functions: the first and third layers provide delamination resistance while the second layer provides surface continuity, collectively resolving the contradiction between ease of repair and delamination resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite repair structure combining multiple fiber layers with different orientations and a matrix material. The fiber reinforcement comprises at least three layers with specific orientation arrangements, creating a composite structure that integrates both ease of application and high delamination resistance. The matrix impregnating these layers further binds them together, forming a unified repair that maintains the non-delaminable nature of the original three-dimensional woven composite material.

Inventive Principle:

Principle #40Composite materials

2Reliability

If three-dimensional woven fiber reinforcement is used in composite material parts, then the material exhibits non-delaminable nature and high mechanical strength, but the repair process becomes complex and difficult to perform

Engineering Contradiction:

Improvenon-delaminable natureVSAvoidease of repair

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The repair method segments the fiber reinforcement into multiple layers (first layer, second layer, third layer) with different orientations. The first layer has fibers oriented perpendicular to the surface at the damaged area, the second layer has fibers parallel to the surface, and the third layer has fibers perpendicular to the surface. This segmentation allows each layer to serve specific functions: the first and third layers provide delamination resistance while the second layer provides surface continuity, collectively resolving the contradiction between ease of repair and delamination resistance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention applies local quality by varying fiber orientations in different regions and layers of the repair. At the damaged area, fibers are oriented perpendicular to the surface in the first and third layers to maximize delamination resistance, while in the second layer and surrounding areas, fibers are oriented parallel to the surface for surface continuity. This localized optimization of fiber orientation allows the repair to maintain high delamination resistance while remaining practical to apply.

Inventive Principle:

Principle #3Local quality

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

The method provides a robust repair with high resistance to delamination, maintaining the material's initial mechanical properties and non-delaminable nature.

Implementation Method 1

the transformation of the resin into a matrix in order to obtain a filling part made of composite material comprising a fiber reinforcement densified by a matrix

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS11607853B2Repair or resumption of manufacture of a composite material part with fibrous three-dimensional woven reinforcement

Publication Date: 2023.03.21 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A method for repairing a part made of composite material includes producing a recessed section by removing the composite material at a damaged area, producing grooves extending on the two faces of the part from edges of the recessed section, producing orifices in the part opening out into the grooves, tree-dimensional weaving of a filling part fiber preforms including a central section having a shape corresponding to the shape of the recessed section and fiber bundles extending from the central section, placing the filling preforms respectively on either face of the part with the fiber bundles in the grooves on the faces of the part and in the orifices such that the fiber bundles open out into the grooves present on the opposite face of the part, impregnating the filling fiber preforms with a precursor resin of a matrix, transforming the resin into a matrix to obtain a filling part.