Separation of the Elastic and Plastic Wave in Electromagnetically Induced Acoustic Emission Testing

In this chapter, a developed electromagnetically induced acoustic emission technique (EMAE) which can be used for nondestructive flaw detection is introduced. This method is different from traditional acoustic emission testing (AET) in the behalf of locally electromagnetic force, which has a big advantage of contactless load. Based on the principle of electromagnetic acoustic transducers (EMAT), it causes the dynamic locally elastic vibration in the area of eddy current during the process of loading at the same time. Acoustic emission sensors receive the stress wave signal, which is the superposition of plastic wave and elastic wave. It is very meaningful to separate the elastic and plastic wave in EMAE. The results could enhance detection accuracy of small crack properties and acoustic emission signal.