Acoustic Emission Testing of Valve Leaks
Acoustic emission testing is often associated with the detection of metal or composite flaws that are active, or grow, while stressed. In steel for example, fatigue crack growth will emit acoustic emission in the 100 to 500 kHz range. Similarly, acoustic emission bursts are detected in composite material from fiber breaks, matrix cracking and other failure mechanisms. The acoustic emission emitted from fatigue cracks in steel and fiber breaks in composites are discrete bursts of acoustic energy. The acoustic emission intensity and rate at which it is generated may be correlated to damage severity. In comparison, acoustic emission testing for valve leak detection analyses the continuous emission of acoustic emission and largely focuses on acoustic emission amplitude. The objectives of acoustic emission inspection of valves are to detect leaks and estimate leak rate. This introductory article summarizes some of the key components of acoustic emission leak detection in valves.