Aircraft Engine Impeller Wheel Defect Detection via Tip Timing
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Solution Overview
Problem
Current methods for detecting defects on aircraft engine impeller wheels are complex, costly, and often require costly instrumentation, making it difficult to detect structural defects in rotating systems, especially those not visible during visual inspections, leading to flight delays and cancellations.
Innovation Solution
A method that acquires deflection signals from impeller blades, correlates them with impact signals, applies modal analysis to identify modal parameters, and monitors their evolution to detect defects, using the 'Tip timing' method without the need for a pulse source or specific electronics on the engine, allowing for on-board signal processing and ground-based analysis to reduce computational load and improve detection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If modal analysis is performed on rotating systems using traditional methods, then defect detection capability is improved, but device complexity and cost increase due to required pulse sources and sensors mounted on rotors
Solution Approach 1:
The patent extracts the modal analysis function from the rotating system itself and performs it externally on captured impact signals. Instead of mounting sensors and pulse sources on the rotor, the system captures deflection signals during rotation and then applies modal analysis offline, separating the measurement function from the rotating component to eliminate complexity.
Solution Approach 2:
The patent introduces an intermediary signal processing system that acts as a mediator between the rotating impeller and the analysis function. The system captures deflection signals during rotation, stores them, and then applies modal analysis externally using computational methods, avoiding the need for direct mounting of instrumentation on the rotating部件.
2Reliability
If control electronics are embarked in the turning part for detection, then detection function is improved, but complexity increases due to thermal and vibratory environment
Solution Approach 1:
The patent extracts the electronic detection and processing functions from the rotating impeller environment. The system uses simple deflection sensors that can withstand the environment, captures signals during rotation, and then performs all complex electronic processing and modal analysis externally in a controlled environment, eliminating the need to embed complex electronics in the thermal and vibratory rotating part.
3Ease of manufacture
If visual inspection is performed on blades, then simplicity of method is maintained, but detection precision is reduced as only visible or accessible defects can be detected
Solution Approach 1:
The patent replaces the mechanical visual inspection method with an acoustic/振动-based detection system. Instead of relying on visual observation or physical access to blades, the system uses deflection sensors to capture vibration signals, applies modal analysis to identify structural defects, and can detect defects even when they are not visible or accessible, thereby improving precision while maintaining operational simplicity.
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 method enables reliable and precise detection of structural defects, reduces computational load on-board, and facilitates defect detection without the need for costly instrumentation, improving signal quality and reducing memory and transmission costs by focusing on impact signals.
Implementation Method 1
The invention takes advantage of the 'Tip timing' method (spot measurement analysis method) already used in the engine
Implementation Method 2
identification of impact by correlations of each of said deflection signals with a detection pulse signal typical of an impact on a sound blade
Implementation Method 3
application of a modal analysis to each of said impact signals to identify the modal parameters relative to each impacted blade
Data Source
AI summary
A method and an on-board system for detecting impact on an impeller wheel of an aircraft engine. Deflection signals representative of the deflections on the blades of the impeller wheel are acquired. Each of the deflection signals is correlated with a pulse signal typical of an impact on a sound blade at the rotation frequency of the engine, in order to identify impacts on the impeller wheel. The impact signals are extracted from among the deflection signals. The impact signals are transmitted to the ground in order that the signals are analyzed to detect defects on the blades of the impeller wheel.