Ultrasonic SHM System
In-situ SHM strategies
In-situ ultrasonic SHM is an advanced technology designed to assess and ensure the integrity of structures through real-time monitoring. This approach employs both active and passive ultrasonic methods to provide a comprehensive evaluation of structural health, making it a vital tool in various industries, including aerospace, civil engineering, and energy.
Active method
Passive method
Bulk wave
Bulk wave thickness monitoring:
This technique focuses on localized monitoring of material thickness using ultrasonic bulk waves. With the in-situ fabricated or installed piezoelectric ultrasonic transducers, ultrasonic bulk waves are transmitted and reflected to detect variations in thickness caused by defects including corrosion, erosion, or material degradation. This method is highly sensitive to minor changes in localized thickness, making it ideal for critical components.
Guided wave
Guided wave monitoring:
Unlike bulk wave monitoring, guided wave techniques allow for the examination of large structural volumes from a a single location. By generating guided waves (such as Lamb or SH waves), engineers can effectively monitor extensive areas like pipelines or aircraft fuselages. This method excels in detecting cracks and other forms of structural damage while reducing the need for numerous ultrasonic transducers.
Acoustic emission/Vibration
Acoustic emission monitoring:
This method passively listens for stress waves generated by active damage processes including crack propagation. In-situ installed/fabricated piezoelectric ultrasonic transducers provide real-time data on structural changes, enabling early detection of potential failures without intrusive inspections.
Vibration monitoring:
Using the lightweight piezoelectric ultrasonic transducer installed or fabricated in-situ to the structure, vibration monitoring captures the structural response to environmental or operation vibrations. Changes in vibration patterns can indicate structural degradation, loose connections, or other issues that may compromise safety.
Algorithm for effective ultrasonic SHM
To maximize the effectiveness of ultrasonic SHM, advanced algorithms are employed for signal processing and damage detection. Techniques such as time-domain analysis, frequency-domain analysis, and wavelet transforms help isolate relevant ultrasonic signals while filtering out noise. Mahcine learning algorithms can classify damage based on the extracted features from the signals, enabling accurate assessments.
Additionally, real-time fusion from active and passive methods enhances decision-making processes. By integrating data from different sources, SHM systems can provide comprehensive insights into the structural conditions, facilitating timely interventions.