Metallic Turbine Blade Edge Repair Using Interlocking Fixing Elements
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Solution Overview
Problem
Existing methods for repairing damaged leading or trailing edge regions of metallic turbine blades are inadequate in providing a stable and long-lasting fix, as they rely solely on substance bonding, which is prone to relative movement and load stress.
Innovation Solution
The method involves forming recesses in the blade walls offset to each other, using protrusions and pin-like fixing elements to create a mechanical connection, combined with substance bonding, to securely attach a replacement part, thereby preventing relative movement and enhancing the durability of the repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only substance bonding is used to attach the replacement part, then the repair process is simple, but the connection is prone to relative movement and load stress, reducing reliability
Solution Approach 1:
The patent combines substance bonding with mechanical fixing elements (pins, clips, or interference fits) to create a hybrid connection system. The replacement part includes both adhesive bonding surfaces and mechanical fixation features, merging two different fixing mechanisms to achieve superior connection stability while distributing loads across multiple fixation methods.
Solution Approach 2:
The connection system uses composite fixing approaches where chemical bonding (substance bonding) is combined with mechanical bonding (physical fixing elements). This composite connection strategy leverages the advantages of both bonding types: the distributed stress distribution of mechanical elements and the gap-filling capability of substance bonding, resulting in enhanced reliability.
2Reliability
If protrusions are inserted into recesses to prevent relative movement, then connection stability improves, but the manufacturing process becomes more complex
Solution Approach 1:
The recesses with protrusions are pre-formed during the manufacturing of the turbine blade or replacement part, rather than being created during the repair process. This preliminary action allows the mechanical interlocking features to be integrated into the production process, reducing the complexity of the repair operation while maintaining connection stability.
3Duration of action of stationary object
If fixing elements extend through overlapping regions to block removal, then service life is extended, but the device complexity increases
Solution Approach 1:
The fixing elements are nested within the overlapping regions of the blade wall and replacement part. The pins or clips are positioned within the geometric overlap zone, creating a compact integrated structure where the fixation mechanism is contained within the structural overlap, minimizing additional complexity while maximizing retention capability.
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 results in a stable and extended service life of the repaired turbine blade by reducing the load on the substance-bonded connection and preventing removal of the replacement part, ensuring a secure and long-lasting repair.
Implementation Method 1
protrusions which in step c) are inserted by form fit in the recesses
Implementation Method 2
the replacement part is mechanically fixed to the turbine blade using fixing elements extending through the mutually overlapping regions, such that this mechanical fixing blocks removal of the replacement part from the cutout against the predetermined insertion direction
Implementation Method 3
connecting the replacement part to the turbine blade by substance bonding
Data Source
AI summary
A method for repairing a damaged leading or trailing edge region of a metallic turbine blade, which has a suction-side blade wall, a pressure-side blade wall and a leading edge and a trailing edge, includes: removing the damaged leading or trailing edge region, with a cutout being formed; providing a replacement part which can be inserted in form-fitting fashion into the cutout and which restores the intended geometry of the turbine blade; inserting the replacement part in form-fitting fashion into the cutout in a predetermined insertion direction, and cohesively connecting the replacement part to the turbine blade, wherein mechanical connection of the replacement part and turbine blade using separate fastening elements is performed in addition to the cohesive connection.