Integrally Bladed Rotor Repair Shape for Mistuning Control
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Solution Overview
Problem
Integrally bladed rotors (IBRs) in gas turbine engines experience unique vibrational characteristics due to manufacturing tolerances and wear, leading to mistuning, which results in uneven blade vibration and increased susceptibility to high cycle fatigue damage, making it challenging to determine an optimal repair shape that addresses these issues effectively.
Innovation Solution
A method and system for repairing IBRs involve performing vibratory analysis on a rotor module, generating computational fluid dynamics models, and iterating potential repair shapes to eliminate undesirable vibratory characteristics, using additive or subtractive manufacturing to apply the selected repair shape, which reduces vibratory stress below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional IBR repair methods are used, then manufacturing simplicity is maintained, but vibratory stress remains high due to mistuning
Solution Approach 1:
The system performs preliminary vibratory analysis and mistuning assessment before repair execution. Multiple potential repair shapes are evaluated in advance through computational modeling to predict their effect on vibratory stress, allowing selection of the optimal repair configuration before actual repair work begins.
Solution Approach 2:
The system modifies geometric parameters of the repair shape (such as blend radius, repair depth, and repair width) to optimize vibratory performance. By adjusting these parameters, the system can reduce mistuning effects and lower vibratory stress on specific blades while maintaining structural integrity.
2Measurement precision
If individual blade repair is performed without considering stack effects, then repair simplicity is maintained, but vibratory analysis accuracy deteriorates
Solution Approach 1:
The system combines multiple IBRs into a virtual stack model for comprehensive vibratory analysis. By analyzing blades within the context of their complete rotor stack environment, the system captures blade-to-blade coupling effects and mistuning phenomena that would be missed in isolated blade analysis, thereby improving prediction accuracy.
3Strength
If larger repair shapes are applied, then defect coverage is improved, but vibratory stress may increase due to mistuning
Solution Approach 1:
The system applies different repair shape characteristics to different locations on the blade. Rather than using a uniform repair approach, the system tailors the repair geometry (blend radius, depth, width) to the specific location and severity of the defect, as well as the local vibratory environment, thereby achieving adequate defect coverage while minimizing adverse vibratory effects.
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A method (1100) of repairing an integrally bladed rotor (IBR) (100) comprises performing (1104) a vibratory analysis of a gas turbine engine rotor module (111) including a first inspected IBR of a first stage with a potential repair shape for the IBR, the first inspected IBR having a defect, determining an undesirable vibratory characteristic of a second inspected IBR of a second stage in the rotor module, iterating (1106) the potential repair shape for the first IBR to eliminate the undesirable vibratory characteristic of the second inspected IBR, and repairing (1110) the first IBR with a selected repair shape based on determining the potential repair shape eliminates the undesirable vibratory characteristic.