Asymmetric Support Collar for Linear Friction Welding Airfoils
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Solution Overview
Problem
Repairing or replacing airfoils in integrally bladed rotors of gas turbine engines is challenging due to their complex design, making conventional methods difficult and expensive.
Innovation Solution
The method involves using linear friction welding with a support collar around the airfoil stub, where the consumable portion of the collar is consumed during welding, ensuring balanced material flow and avoiding contamination of the weld bond, and machining away excess material post-welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If linear friction welding is used to attach airfoils to the rotor hub, then productivity and repair efficiency are improved, but material pollution in the weld joint occurs due to unbalanced material flow
Solution Approach 1:
The collar is designed with asymmetric geometry where the first portion (engaging the airfoil stub) has different dimensions than the second portion (engaging the replacement airfoil). Specifically, the first portion has a smaller lateral dimension than the second portion, creating unbalanced material flow during welding that directs excess material away from the weld joint toward the collar, preventing contamination of the bond between airfoil and hub.
Solution Approach 2:
The collar acts as an intermediary component between the airfoil stub and the replacement airfoil during the welding process. It provides a sacrificial element that absorbs excess material flow and protects the critical weld joint from contamination, allowing the welding process to proceed efficiently while maintaining joint integrity.
2Manufacturing precision
If a support collar is used during linear friction welding, then manufacturing precision and weld quality are improved, but device complexity increases
Solution Approach 1:
The collar is segmented into distinct functional portions: a first portion that engages the airfoil stub and a second portion that engages the replacement airfoil. Each portion has optimized dimensions for its specific function, allowing the collar to provide precise control over material flow and weld quality while maintaining a relatively simple overall structure that can be manufactured using standard machining processes.
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 allows for efficient and effective attachment of new airfoils to damaged ones in integrally bladed rotors, maintaining structural integrity and reducing repair costs by preventing material pollution in the weld joint.
Implementation Method 1
performing linear friction welding to add an airfoil to the airfoil stub
Data Source
AI summary
An example method of attaching an airfoil for an integrally bladed rotor includes placing a support collar in an installed position around at least a leading edge and trailing edge of an airfoil stub to be repaired in an integrally bladed rotor. The support collar and the airfoil stub together have a midline that is positioned between opposing, laterally outer surfaces of the airfoil stub when the support collar is in the installed position. The method performs linear friction welding to add a replacement airfoil to the airfoil stub.