Rotor Interface Stiffness Detection in Narrow Spaces Using Ultrasonics
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Solution Overview
Problem
Existing interface stiffness detection methods for aero-engine rotors face challenges such as incapability of in-situ detection, poor accessibility due to narrow internal spaces, and poor robustness due to uncertainty in sensing boundary parameters, leading to increased difficulty and reduced measurement performance.
Innovation Solution
An in-situ ultrasonic detection method and device based on microwave transmission-line theory, utilizing a clamping mechanism with electromagnets and springs for probe positioning and pressure, and a calculation method to eliminate sensing boundary influences, enabling synchronous rotation and improved coaxiality of probes for robust stiffness measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an open detection device is used for interface stiffness detection, then the detection can be performed with simple structure, but the device cannot access the narrow internal spaces of aero-engine rotors
Solution Approach 1:
The detection device is nested within the rotor structure, with the upper and lower probes positioned inside the rotor's internal space. The device utilizes the rotor's own geometry to accommodate the detection components, allowing the probes to reach the interface stiffness measurement positions without requiring external access.
Solution Approach 2:
The detection approach transitions from external open-space detection to internal confined-space detection by positioning probes along the axial dimension of the rotor. The upper probe is placed on the upper surface of the disk and the lower probe on the lower surface, utilizing the thickness dimension to perform detection within the narrow internal space.
2Device complexity
If traditional ultrasonic detection is performed without considering sensing boundary parameters, then the detection process is simple, but the measurement performance deteriorates due to boundary uncertainty
Solution Approach 1:
The sensing boundary parameters (couplant layer thickness and acoustic impedance) are extracted and explicitly modeled in the theoretical framework. By separating these boundary effects from the interface stiffness measurement, the method can mathematically eliminate their influence, achieving accurate measurements despite their presence in the physical system.
Solution Approach 2:
The method transforms the measurement approach by changing from direct interface stiffness measurement to a multi-parameter analysis that includes transmission coefficient, reflection coefficient, and sensing boundary parameters. By measuring multiple parameters and using theoretical modeling, the system can solve for interface stiffness while accounting for boundary uncertainties.
3Reliability
If in-situ detection is performed within the rotor, then the measurement can be performed on actual engine components, but the device structure becomes complex to accommodate narrow space constraints
Solution Approach 1:
The detection device is designed with universal components that can be adapted to different rotor configurations. The electromagnetic adsorption mechanism provides a universal clamping solution that works on various rotor geometries, while the probe assembly can be positioned to detect interface stiffness at different locations within the rotor structure.
Solution Approach 2:
The upper and lower probe assemblies are merged into a coordinated detection system that operates simultaneously. The electromagnetic adsorption mechanism combines magnetic force with spring pressure to achieve both secure positioning and controlled contact force, merging multiple functions into an integrated clamping system.
4Measurement precision
If electromagnetic adsorption with spring pressure is used to clamp probes, then the probe positioning and contact force are improved, but the device requires additional electromagnetic components
Solution Approach 1:
The traditional purely mechanical clamping system is replaced with an electromagnetic-spring hybrid system. The electromagnetic adsorption mechanism uses magnetic fields to provide the primary clamping force, eliminating the need for complex mechanical actuators, while springs provide supplemental pressure and ensure consistent contact force between the probes and the rotor surfaces.
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
Enables in-situ interface stiffness detection in narrow spaces with improved repeatability and stability, reducing the impact of sensing boundary uncertainties and enhancing measurement robustness.
Implementation Method 1
pressing the upper ultrasonic probe 28 and the lower ultrasonic probe 36 at a position to be detected through a mutual adsorption effect between an electromagnet 12 and an adsorption cylinder 16
Implementation Method 2
emitting ultrasonic signals through the upper ultrasonic probe 28 and the lower ultrasonic probe 36 to obtain a transmission coefficient B1, an upper surface reflection coefficient C12 and a lower surface reflection coefficient C43
Data Source
AI summary
The present invention belongs to the technical field of interface stiffness detection, and discloses an in-situ ultrasonic detection method and device for interface stiffness of aero-engine rotors based on a microwave transmission-line theory. The in-situ ultrasonic detection device for interface stiffness of aero-engine rotors is based on a device matrix and forms the distribution form of an upper and a lower structures through a middle connection structure. Two probes achieve extension and contraction movement by using actuator turntables as the reference respectively. The detection device is positioned and fixed through a clamping mechanism, provides the clamping displacement of the probes through an electromagnet and an adsorption cylinder, and provides the clamping forces of the probes through compression springs. The in-situ ultrasonic detection device for interface stiffness of aero-engine rotors in the present invention can reduce the random influence of sensing boundaries based on the microwave transmission-line theory.