Calibration Methods of Acoustic Emission Sensors
نویسنده
چکیده
This study examined outstanding issues of sensitivity calibration methods for ultrasonic and acoustic emission transducers and provides workable solutions based on physically measureable quantities, laser-based displacement measurement in particular. This leads to mutually consistent determination of transmitting and receiving sensitivities of sensors and transducers. Methods of circumventing problems of extraneous vibrations on free transmitters are used, giving the foundation for face-to-face calibration methods. Working on many ultrasonic and acoustic emission transducers, their receiving and transmitting sensitivities are found to be always different, while their ratios exhibit unexpected similarity. This behavior is attributed to monopolar pulse generation and bipolar received signals due to electrical charge transfer during elastic wave motion and reflection on the back face. This is verified through a quantitative piezoelectric sensing experiment. Displacement vs. velocity calibration terminology is clarified, redefining the "V/µbar" reference for contact sensor calibration. With demonstrated differences in the transmitting and receiving sensitivities of transducers, the requirement of the Hill-Adams equation invalidates the basic premise of the currently formulated reciprocity calibration methods for acoustic emission transducers. In addition, the measured reciprocity parameter for the case of through-transmission significantly deviates from the approximate theoretical prediction. It is demonstrated that three methods provide reliable sensor calibration results that are complimentary among them.
منابع مشابه
Health Monitoring for Composite under Low-Cycle Cyclic Loading, Considering Effects of Acoustic Emission Sensor Type
Composites have been widely used in the aerospace industry. Due to the requirement of a high safety for such structures, they could be considered for health monitoring. The acoustic emission approach is one of most effective methods for identifying damages in composites. In this article, standard specimens were made from carbon fibers and the epoxy resin, with the [03/902/...
متن کاملCorrection: Ono, K. Calibration Methods of Acoustic Emission Sensors. Materials 2016, 9, 508
The author wishes to make the following corrections to this paper [1].[...].
متن کاملCluster Analysis of Acoustic Emission Signals for Carbon/Epoxy Composite in Four-point Bending Test (RESEARCH NOTE)
Due to the extensive use of composites in various industries and the fact that defects reduce ultimate strength and efficiency during operation, detection of failures in composite parts is very important. The aim of this paper is to use Acoustic Emission (AE) non-destructive method in four-point bending test of carbon/epoxy composite to analyze and examine the failure mechanisms. This method is...
متن کاملIntegrating Broad-Band High-Fidelity Acoustic Emission Sensors and Array Processing to Study Drying Shrinkage Cracking in Concrete
Array processing of seismic data provides a powerful tool for source location and identification. For this method to work to its fullest potential, accurate transduction of the unadulterated source mechanism is required. In our tests, controlled areas of normal-strength concrete specimens were exposed to a low relative humidity at an early age to induce cracking due to drying shrinkage. The spe...
متن کاملBar-Wave Calibration of Acoustic Emission Sensors
This study extended a bar-wave calibration method for acoustic emission (AE) sensors. It combined laser interferometer displacement measurements and the wave propagation medium of a long bar, excited at its end with an ultrasonic transducer driven by a pulser. Receiving bar-wave sensitivities of 16 types of AE sensors were measured and compared to their receiving sensitivities to normally incid...
متن کامل