Pre-Cured Composite Repair Patch for Fast Structural Rework
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Solution Overview
Problem
Composite structures used in aircraft construction are prone to damage and deformation, requiring time-consuming repair methods, and existing repair solutions do not efficiently address the need for quick and effective rework of highly loaded primary and secondary structural components.
Innovation Solution
A method involving the use of alternating layers of film-adhesives and pre-cured ply stacks to form a patch over the damaged area, with each layer extending beyond the repair area to ensure proper bonding and stiffness within designed tolerances, and a repair kit comprising differently sized film-adhesives and pre-cured ply stacks for efficient rework.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional repair methods are used for composite structures, then the repair can be performed with simple materials and equipment, but the repair process is time-consuming and requires specialized skills
Solution Approach 1:
The patch is divided into multiple pre-cured ply stacks of different sizes (first pre-cured ply stack, second pre-cured ply stack) that can be applied in a modular fashion. This segmentation allows for faster application compared to single-piece patches while maintaining structural integrity through the layered configuration.
Solution Approach 2:
The ply stacks are pre-cured before application to the damaged area. This preliminary curing action eliminates the need for on-site curing equipment and reduces the overall repair time, as the patches are ready-to-apply structural components that only require bonding to the composite structure.
2Reliability
If the patch extends beyond the repair area to ensure proper bonding and stiffness, then the structural integrity is improved, but the amount of material and complexity increases
Solution Approach 1:
Different ply stacks are used with different extension dimensions tailored to specific repair needs. The first pre-cured ply stack extends beyond the repair area in a first dimension, while the second pre-cured ply stack extends in a second dimension, allowing localized reinforcement where structurally necessary rather than uniform extension in all directions.
Solution Approach 2:
The patch utilizes composite material construction with multiple ply stacks bonded together with film-adhesive. This composite structure provides enhanced structural integrity and stiffness distribution, allowing the patch to extend less far beyond the repair area while still achieving the required mechanical performance through the synergistic combination of multiple layers.
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
This method allows for rapid and effective repair of composite structures by forming a patch with the required stiffness, enabling quick rework of composite structures without the need for specialized equipment or skilled technicians, thus minimizing downtime and improving the structural integrity of aircraft components.
Implementation Method 1
placing a first film-adhesive over the area of the composite structure requiring rework... placing a first pre-cured ply stack over the first film-adhesive... placing a second film-adhesive over the first pre-cured ply stack
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Provided is a method a method for reworking an article. The method includes forming a patch (500) over an area of a composite structure (201) requiring rework. The forming includes placing a first film-adhesive (331) over the area of the composite structure requiring rework, wherein the first film-adhesive extends over a first surface area of the structure including beyond an entirety of the area requiring rework, placing a first pre-cured ply stack (333) over the first film-adhesive, wherein the first pre-cured ply stack extends over a second surface area of the composite structure; placing a second film-adhesive (335) over the first pre-cured ply stack, wherein the second film-adhesive extends over a third surface area of the composite structure; and placing a second pre-cured ply stack (337) over the second film-adhesive, wherein the second pre-cured ply stack extends over a fourth surface area of the composite structure.