Resonance Probe Ground Isolation for Accurate Ultrasonic Inspection
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Solution Overview
Problem
Existing non-destructive testing methods for aircraft propulsion system components suffer from inaccuracies due to parasitic capacitance between sense and drive piezoelectric transducers, complicating the interpretation of ultrasonic vibration signals.
Innovation Solution
A resonance inspection system with a galvanically isolated grounding subassembly, featuring separate grounds for the sense and drive circuits, and a double-stacked piezoelectric transducer configuration to minimize parasitic capacitance and enhance signal accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single ground is used for both sense and drive circuits, then device complexity is reduced, but parasitic capacitance between circuits degrades measurement precision
Solution Approach 1:
The grounding subassembly is segmented into separate first and second grounds, with the first ground connected to the sense circuit and the second ground connected to the drive circuit. This segmentation eliminates parasitic capacitance between the sense and drive circuits by providing independent ground paths, thereby improving measurement precision while maintaining manageable device complexity through modular implementation.
2Measurement precision
If separate grounds are used for sense and drive circuits, then parasitic capacitance is reduced, but device complexity increases
Solution Approach 1:
A coupling capacitor is introduced as an intermediary element between the sense and drive circuits, allowing signal coupling while blocking direct DC paths and minimizing parasitic capacitance effects. This intermediary approach enables separate grounding for both circuits (improving signal accuracy) while the capacitor provides a controlled coupling mechanism that manages the increased device complexity.
3Measurement precision
If double-stacked piezoelectric transducers are used, then parasitic capacitance is minimized, but manufacturing complexity increases
Solution Approach 1:
The piezoelectric transducer assembly is segmented into separate sense and drive transducer elements stacked in series, with independent electrical connections for each. This segmentation allows optimization of each transducer's performance and minimizes parasitic capacitance between elements, improving measurement precision. The modular segmented structure also facilitates standardized manufacturing processes despite the increased assembly complexity.
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 system provides more accurate measurement of ultrasonic signals, enabling effective identification of internal defects in propulsion system components with reduced interference, facilitating efficient and precise inspections.
Implementation Method 1
The probe includes a sense piezoelectric transducer and a drive piezoelectric transducer
Implementation Method 2
complicating the interpretation of ultrasonic vibration signals
Implementation Method 3
resonance-based component inspection
Data Source
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AI summary
A resonance inspection system includes a probe (74; 702) and a control assembly (72). The probe (74; 702) includes a sense piezoelectric transducer and a drive piezoelectric transducer (80B). The control assembly (72) includes a measurement channel (90), a signal generator (88), and a grounding subassembly (400). The measurement channel (90) is electrically connected to the sense piezoelectric transducer by a sense circuit (406). The signal generator (88) is electrically connected to the drive piezoelectric transducer (80B) by a drive circuit (408). The grounding subassembly (400) includes a first ground (402) and a second ground (404). The first ground (402) is disposed on the sense circuit (406). The second ground (404) is disposed on the drive circuit (408). The first ground (402) is galvanically isolated from the second ground (404).