Adhesive Composite Patch Repair for Fatigue Cracks in Metal Structures
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Solution Overview
Problem
Current repair methods for cracked aluminum structures in vehicles, aircraft, and ships are either costly and ineffective in preventing further crack growth or lack the structural integrity to withstand operational stresses, leading to increased maintenance costs and performance issues.
Innovation Solution
The use of fiber reinforced metal matrix composite tape, adhesively bonded to the metal structure, which can cover at least 25% of the defect area, with fibers oriented across the crack to arrest or retard crack growth, and optionally a second layer at an angle for enhanced reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current temporary repair methods are used to seal cracked aluminum structures, then sealing effectiveness is improved, but crack growth prevention capability deteriorates
Solution Approach 1:
The patent applies composite materials by bonding carbon fiber reinforced polymer (CFRP) tape to the aluminum structure. The CFRP composite provides both sealing capability and structural reinforcement, simultaneously addressing both sealing effectiveness and crack growth prevention. The carbon fibers in the CFRP tape bridge the crack and distribute stresses, preventing further crack propagation while the adhesive layer seals the crack area.
2Strength
If permanent repairs of cracked components are performed, then structural integrity is improved, but cost and practicality deteriorate
Solution Approach 1:
The patent segments the repair solution into a modular CFRP tape patch that can be independently applied to the cracked area. This segmented approach allows for localized reinforcement without requiring complete component replacement or complex permanent repair procedures. The tape can be cut to size and applied only where needed, reducing material costs and simplifying the repair process while restoring structural integrity.
Solution Approach 2:
The patent introduces an adhesive layer as an intermediary between the CFRP tape and the aluminum structure. This adhesive mediator enables easy bonding of the reinforcement tape to the existing structure, facilitating a practical and cost-effective repair that can be performed without complex joining processes. The adhesive system allows for simple application and removal, improving ease of manufacture and repair practicality.
3Strength
If fiber reinforced metal matrix composite tape is applied to cover defects, then crack growth arrest capability is improved, but application complexity increases
Solution Approach 1:
The patent employs thin film CFRP tape that is flexible and can be conformally applied to the aluminum structure surface. This thin film format simplifies application compared to rigid composite panels, allowing the tape to be easily positioned and bonded over the cracked area. The flexible nature of the thin film tape reduces application complexity while maintaining crack growth arrest capability through the embedded carbon fibers.
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 approach provides a low-cost, field-friendly, and non-corrosive patch that effectively increases the fatigue life of the structure, minimizes collateral damage, and prevents further crack growth, offering a cost-effective solution for both temporary and permanent repairs.
Implementation Method 1
adhesively bonding the at least one layer of fiber reinforced metal matrix composite tape to the metal structure
Data Source
AI summary
A method for repairing a crack in ships or other structures that includes adhesively applying fiber reinforced metal matrix composite tape across the crack of the structure to reduce propagation of the crack and provide additional structural stability until the crack can be permanently repaired.