The instrumentation required to detect discrete acoustic emission is sophisticated. A straightforward AE instrument hardware design includes a transducer, preamplifier, bandpass filter, amplifier & several digital signal processors. The exact way in which signals are gated, filtered and interpreted adds complexity because of background noise present during the measurement. With background noise removed by the signal processors, the next problem is correlating the AE signal level & the status of the material/structure that is under test.
Our AE instruments use proprietary software to perform extensive signal analysis after the hardware amplification and processing. The combined results of our acoustic emission instrument hardware and software is a complete characterization of the suspect AE (signal) and thus, a reliable characterization of the source phenomenon of the acoustic emission, be it caused by a crack, leak, friction, etc.
We have developed proprietary AE software since the early 70's!
Similar apparatus can be used to monitor acoustic and low frequency ultrasonic output from a variety of sources, such as defective rotating bearings, leaking steam pipes or electrical discharge in transformers, etc. Although these sources are not "classical" acoustic emission sources, measurement from them reveals the condition of industrial machinery and effectively reduces the risk of catastrophic failures and helps avoid expensive shut-downs.
AE instrumentation typically consists of:
- A sensor that converts a stress (sound) wave to an electrical signal
- A low noise amplifier that raises the signal to a usable level
- Signal processing electronics for feature extraction and waveform capture
- Microprocessor, & DSP based parallel distributing processing instrumentation
- Knowledge-based software for easy analysis, defect correlation & development of expert systems that comply with demanding AE Standards
- Decision and feedback electronics to utilize the information