Aero-Engine Weld Crack Stoppers for High-Cycle Fatigue
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Solution Overview
Problem
Aircraft engine components exposed to high cycle fatigue (HCF) often require over-dimensioning to prevent crack propagation, leading to increased weight and potential fuel consumption issues, as existing methods focus on repairing cracks rather than preventing their initiation and propagation along weld lines.
Innovation Solution
A method of manufacturing aero-engine components involves forming crack stoppers, which are discrete metal deposits across weld lines, acting as barriers to limit crack propagation, using metal deposition techniques to add material along the weld lines, thereby preventing crack growth and extending inspection intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If structural elements are over-dimensioned to prevent crack propagation in HCF regions, then crack resistance is improved, but component weight increases
Solution Approach 1:
The patent applies local reinforcement by adding material specifically at weld lines where cracks are most likely to initiate and propagate. Instead of globally over-dimensioning the entire structural element, the invention creates localized crack stoppers at critical weld locations. This allows the bulk of the structure to maintain its original lightweight design while providing targeted crack propagation barriers only where needed, thus resolving the contradiction between crack resistance and overall weight.
2Reliability
If weld lines are avoided in critical areas, then crack initiation risk is reduced, but structural design flexibility and connectivity are limited
Solution Approach 1:
The invention applies preliminary protective action by forming crack stoppers at weld lines before any crack can initiate or propagate. The crack stoppers are created as discrete metal deposits that span across the weld line, establishing a barrier in advance. This allows weld lines to be used freely in structural design without compromising reliability, as the preliminary crack stoppers prevent crack propagation even if initiation occurs at the weld.
3Measurement precision
If regular inspections are performed to detect cracks, then crack detection capability is maintained, but maintenance frequency and operational downtime increase
Solution Approach 1:
The crack stoppers act as a beforehand cushioning measure that limits crack propagation to a maximum length between stoppers. Even if a crack initiates at a weld line, it cannot propagate indefinitely but is arrested by the discrete metal deposits. This cushioning effect extends the time between required inspections, as cracks are limited in growth and can be detected at earlier stages, reducing maintenance frequency while maintaining safety.
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 effectively limits crack propagation along weld lines, allowing for the production of lightweight components by preventing crack growth, thus reducing the weight and maintenance frequency of aircraft structures while maintaining structural integrity.
Implementation Method 1
adding material across the weld line, thereby forming a crack stopper for limiting crack propagation along the weld line
Data Source
Figure 1~2
Figure 3A
Figure 3B~3C
AI summary
A method for joining two structural elements (26, 28) by welding, in particular by butt welding, is disclosed. The method comprises the following steps: - forming a weld line (30) joining the two structural elements; - adding material (32) across the weld line (30), thereby forming one or more crack stoppers (34) for limiting crack propagation along the weld line. The one or more crack stoppers (34) each having a limited extension along the weld line (30) as seen in relation to a length of the weld line. A structural system comprising two structural elements joined by the method is disclosed. Especially, the method may be applied to components of aircraft engines.