Composite Countersink Repair Patch Nesting

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Solution Overview

Problem

Inappropriate countersinks with excessive diameters and depths in composite components lead to inefficient repair methods that compromise the structural strength of assembled components, requiring high effort and resulting in reduced bearing strength capabilities.

Innovation Solution

A method involving the preparation and placement of a repair patch with a wet laminate layup, using polytetrafluorethylene tape and a pressure tool to correct the countersink, ensuring alignment and fixing the patch within the countersink to restore original structural strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If filling with compound material or installing repair patch is used to correct inappropriate countersink, then the repair process can be performed, but the bearing strength capability is significantly reduced compared to original structure strength

Engineering Contradiction:
Improverepair process feasibilityVSAvoidbearing strength capability
Core Design Contradiction:
Ease of repairVSStrength

Solution Approach 1:

The repair patch is pressed into the inappropriate countersink, nesting the patch within the existing countersink cavity. This allows the repair to utilize the existing countersink space while restoring structural strength through the integrated patch-material combination.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The repair method uses composite material construction where a repair patch (fabric reinforcement) is combined with compound material (resin/epoxy) to create a repaired countersink that restores bearing strength capability comparable to the original structure.

Inventive Principle:
Principle #40Composite materials

2Ease of repair

If indirect treatment methods (filling or repair patch installation) are used to correct inappropriate countersink, then the countersink can be repaired, but additional design space is required in the surrounding area

Engineering Contradiction:
Improvecountersink repair capabilityVSAvoiddesign space requirement
Core Design Contradiction:
Ease of repairVSArea of stationary object

Solution Approach 1:

The repair patch is nested within the existing countersink boundaries, allowing the repair to be contained within the original footprint. This eliminates the need for additional design space surrounding the inappropriate countersink while still providing effective repair.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Ease of repair

If conventional repair methods are used to correct inappropriate countersink, then the repair can be performed, but high effort and time are required with low effective repair results

Engineering Contradiction:
Improverepair process executionVSAvoidrepair efficiency
Core Design Contradiction:
Ease of repairVSProductivity

Solution Approach 1:

The repair patch is prepared in advance with the correct dimensions and material composition before installation. This preliminary preparation streamlines the actual repair process, reducing the effort and time required during the correction operation while ensuring effective repair results.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The repair patch is designed to be self-contained with all necessary materials and structural properties integrated into a single component that can be installed as one unit, eliminating the need for multiple separate operations and reducing overall repair effort and time.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3248768B1A method of correcting an inappropriate countersink in a composite component
Publication Date: 2018.10.03 AIRBUS HELICOPTERS DEUT GMBH
  • EP3248768B1 patent drawingFigure 1~4
  • EP3248768B1 patent drawingFigure 5~7
  • EP3248768B1 patent drawingFigure 8~10

AI summary

The invention is related to a method of correcting, in a composite component (1), an inappropriate countersink (2a) with an inappropriate maximum diameter (2b) and/or depth, the inappropriate countersink (2a) being provided in the composite component (1) at a fixation opening (10) having a first opening diameter (1d), the method comprising at least the steps of: Preparing a repair patch (4); Arranging the repair patch (4) on the composite component (1) in an area (2d) surrounding the inappropriate countersink (2a); Pressing the repair patch (4) at least partly into the inappropriate countersink (2a) by means of an associated pressure tool (6); and Fixing the repair patch (4) in the inappropriate countersink (2a).