Papers by Author: Kanji Ono

Abstract: The purpose of this study is to find out the method to detect AE signals at around the notch tip and to evaluate the AE signal characteristics for the basemetal, PWHT(post weld heat treatment) and weldment specimens of SA-516 steel during bend test. AE signals were produced in the process of plastic deformation. AE signal strength and amplitude of the weldment was the strongest, followed by PWHT specimen and basemetal. More AE signals were produced from the weldment because of the oxides, and discontinuous mechanical properties. The stronger AE signal strength, amplitude and more AE event counts for the weldment were shown.

Abstract: This paper reviews various approach used in acoustic emission (AE) testing of structures so that further improvements can be realized in this important application of AE technology. In the past half century, many successful AE tests of structures have been completed, but quite often details remained private. Here, we attempt to organize the AE methodology in four steps. 1. Primary sources of brittle fracture, micro or macro cracks in contrast to secondary sources of friction or fretting, rust, etc. 2. Kaiser effects, arising from the irreversibility of AE, allow the detection of prior loading level and of damage states. 3. Source Location: This approach identifies the area of integrity loss. 4. Source Characterization: Combined AE parameters give good insight to the flaw types, but many other methods, including attenuation-corrected signal amplitude, signal frequency, waveform and wave propagation analysis and moment tensor analysis, may be useful. Avenues for better AE technology are suggested.