Low-Power Guided Wave Damage Localization Using VNA Resonance
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Solution Overview
Problem
Conventional ultrasonic guided wave techniques for damage localization in structures require high voltage burst excitations, which are unsafe and unsustainable for large structures like airplane wings, bridges, and wind turbine blades, necessitating a method for low power ultrasonic guided wave damage localization.
Innovation Solution
A method and system using low power ultrasonic guided waves that employ a Vector Network Analyzer (VNA) sweep of a predefined frequency range to form guided wave resonance spectra, followed by Inverse Fast Fourier Transform (IFFT) to obtain a time domain pulse propagation picture, enabling damage localization through pulse echo analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high voltage burst excitation is used to induce symmetric and asymmetric modes in thin plates, then defect detection capability is improved, but safety and energy sustainability deteriorate
Solution Approach 1:
The patent changes the excitation parameters from high voltage burst mode to low voltage continuous wave mode. Specifically, it uses low voltage (e.g., 10-100 volts) continuous sinusoidal waves instead of high voltage (100-1000 volts) burst excitations, fundamentally altering the operating conditions to achieve both safety and detection capability
Solution Approach 2:
The patent employs periodic continuous wave excitation instead of intermittent burst excitation. By using continuous sinusoidal waves at specific frequencies that match the resonant frequencies of the structure, it achieves sustained vibration without the high voltage spikes associated with burst mode, thereby improving safety while maintaining detection effectiveness
2Measurement precision
If high voltage burst excitation is used for ultrasonic guided wave probing, then damage localization accuracy is improved, but energy consumption increases
Solution Approach 1:
The patent fundamentally changes the excitation parameters by switching from high voltage burst mode to low voltage continuous wave mode. This parameter change reduces energy consumption while maintaining localization accuracy through the use of resonant frequency excitation that efficiently couples energy into the structure without requiring high voltage pulses
Solution Approach 2:
The patent utilizes mechanical resonance to enhance the efficiency of energy transfer. By exciting the structure at its resonant frequencies using low voltage continuous waves, it achieves sustained vibration and effective damage localization with minimal energy input, avoiding the high energy consumption of high voltage burst excitation
3Measurement precision
If traditional burst mode excitation is used for guided wave probing, then defect identification capability is improved, but testing time increases
Solution Approach 1:
The patent uses periodic continuous wave excitation at resonant frequencies to sustain vibrations throughout the structure. This continuous excitation allows for faster signal acquisition and processing compared to burst mode, reducing testing time while maintaining defect identification capability through the consistent vibration signals
Solution Approach 2:
The patent employs continuous wave excitation that maintains useful vibrational action throughout the testing process. Unlike burst mode which has idle periods between pulses, the continuous excitation ensures that the structure is continuously vibrating at resonant frequencies, enabling faster and more efficient defect detection without compromising identification accuracy
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 method ensures safety and sustainability by reducing power requirements, making it suitable for structures where high voltage usage is prohibited, and significantly shortens testing time by using pre-trained machine learning models.
Implementation Method 1
a first piezoelectric transmitter (Tx) and a second piezoelectric receiver (Rx) are placed on a metal sheet
Implementation Method 2
Ultrasonic guided waves are routinely used in Non-Destructive Testing (NDT) for defect identification and localization in metal sheets or other complex structures
Implementation Method 3
performing an Inverse Fast Fourier transform (IFFT) on the primary guided wave resonance spectra to obtain a primary time domain pulse propagation picture
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
Use of ultrasonic guided waves for damage identification and localization is not new in Non-Destructive Testing/Evaluation. However, most of the time it is performed with high voltage pulse excitations that use several hundreds of volts in the form of a short burst, thus making it unsafe and unsustainable for defect localization in large structures. Present disclosure provides a method and a system for damage localization using low power ultrasonic guided waves. The system of the present disclosure uses a Vector network analyzer (VNA) sweep of a defined frequency range of low signal amplitude on a structure to form guided wave resonance spectra. Then, the system performs an Inverse Fast Fourier transform (IFFT) on the guided wave resonance spectra to obtain a time domain pulse propagation picture. Thereafter, the system uses a pulse echo based analysis technique based on time domain pulse propagation picture to locate damage position in the structure.