Magnetostrictive Thin-Film Sensors for High-Temperature Crack Detection
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Solution Overview
Problem
Current technologies lack effective, on-board sensors for real-time detection and monitoring of cracks in high-value assets like turbine engines, especially in harsh thermal and stress environments, with limited accessibility and high rotational speeds, making continuous inspection challenging.
Innovation Solution
A monolithically integrated, multi-layered thin-film sensor system using magnetostrictive materials with wireless connectivity, capable of generating and detecting ultrasonic waves, and operating at high temperatures, for real-time crack detection and structural health management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional depot NDE techniques are used for crack detection, then measurement precision is improved, but ease of operation deteriorates due to required component disassembly and controlled environment
Solution Approach 1:
The patent replaces traditional mechanical NDE techniques (ultrasonic, eddy current, magnetic particle inspection requiring manual probes and controlled environments) with an integrated piezoelectric sensor system that uses electrical excitation and wireless communication. The sensor array with pulsed laser excitation and photodetector reception eliminates the need for physical contact probes, enabling crack detection in rotating components without disassembly or controlled environment requirements.
Solution Approach 2:
The sensor system is self-powered through energy harvesting from the component's operational vibrations and electromagnetic fields. The piezoelectric sensors generate electrical power from mechanical vibrations, while the wireless communication module transmits data without external power connections. This self-sufficient design enables continuous monitoring during normal operation without requiring component shutdown or external intervention.
2Productivity
If on-board sensors are implemented for real-time monitoring, then productivity is improved through continuous inspection, but device complexity increases due to integration requirements in harsh environments
Solution Approach 1:
The patent designs a multi-functional sensor array that simultaneously performs crack detection, structural health monitoring, and wireless data transmission. The piezoelectric sensors serve dual purposes as both actuators for generating ultrasonic waves and receivers for detecting reflected waves from cracks. The integrated wireless module combines power harvesting, signal processing, and communication functions in a single compact unit suitable for embedding in turbine blades and rotating components.
Solution Approach 2:
The sensor array utilizes thin-film piezoelectric materials deposited directly onto the surface of rotating components. These flexible thin-film sensors conform to curved surfaces and withstand high rotational speeds, thermal cycling, and vibrational loads. The thin-film architecture enables integration into existing component geometries without significant modification, reducing manufacturing complexity while enabling continuous monitoring during operation.
3Ease of operation
If acoustic emission sensors are used for crack detection, then ease of operation is improved, but measurement precision deteriorates due to difficulty in extracting cracking signatures from background noise
Solution Approach 1:
The patent employs periodic pulsed laser excitation at specific frequencies to generate ultrasonic waves that propagate through the component structure. By using periodic excitation at resonant frequencies, the system enhances the amplitude of reflected waves from cracks while maintaining a consistent background signal. The periodic nature of the excitation enables synchronous detection techniques that filter out random background noise and isolate crack-related acoustic emissions, significantly improving measurement precision.
Solution Approach 2:
The system utilizes mechanical vibration through piezoelectric actuators that generate controlled ultrasonic waves incident on potential crack locations. The vibration frequency and amplitude are precisely controlled to maximize reflection from crack surfaces while minimizing background interference. By analyzing the reflected vibration signals and their temporal characteristics, the system accurately distinguishes crack signatures from normal operational vibrations, achieving high measurement precision with simple sensor installation.
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 enables continuous, real-time monitoring of cracks with enhanced sensitivity and reliability, reducing the probability of failure in high-value assets by integrating on-board sensors with physics-based analytical models for damage accumulation and decision-making.
Implementation Method 1
distributed thin-film magnetostrictive sensors that are integrated onto the component surface
Data Source
AI summary
Systems and methods for flaw detection and monitoring at elevated temperatures with wireless communication using surface embedded, monolithically integrated, thin-film, magnetically actuated sensors, and methods for fabricating the sensors. The sensor is a monolithically integrated, multi-layered (nano-composite), thin-film sensor structure that incorporates a thin-film, multi-layer magnetostrictive element, a thin-film electrically insulating or dielectric layer, and a thin-film activating layer such as a planar coil. The method for manufacturing the multi-layered, thin-film sensor structure as described above, utilizes a variety of factors that allow for optimization of sensor characteristics for application to specific structures and in specific environments. The system and method integrating the multi-layered, thin-film sensor structure as described above, further utilizes wireless connectivity to the sensor to allow the sensor to be mounted on moving components within the monitored assembly.