Experimental Study On Electromagnetically Acoustic Emission Technique

Electromagnetically acoustic emission technique (EMAE) is a recently developed non-destructive test technique. Using electromagnetic stimulation to produce acoustic emission (AE) signals is used to locate small flaws or cracks in thin-walled structures nondestructively to allow inspection of specific areas without loading the whole structure. This method is often used in aircraft, large complex castings and multi-bonding materials, and it has good potential development in detecting the type and amount of defect. At present, its mechanism is unclear as well as the relationship between the electromagnetic stimulation and acoustic emission. Under the background, the paper does theory and experiment research on electromagnetically acoustic emission.Firstly, the paper builds the finite element model of electromagnetic acoustic emission, analyses the specimen deformations in different conditions, compares effects of several load factors on electromagnetic acoustic emission and analyses specimen temperature.Secondly, considering the effect of Kaiser Effect, the buffer circuit of acoustic emission power supply is designed that can prevent overcurrent. Taking measure of low lever switching on and negative voltage switching off, it can drive power supply working well in Strong magnetic field.Thirdly, pencil lead break tests have done the testing on sensors and the whole acoustic emission system, and the acoustic emission experiment is conducted.