Study Of Wave Motion In Elastic Plate By Using Technology Of AE

In this paper base on theories of wave motion and acoustic emission orientation of defects in a plate, scattering of AE wave in a plate with a hole and the problem of wave motion while the plate is operated under impact load are full studied from the angles of theory, experimentation and ansysis beginning from the progation of stress wave in a plate and AE testing. The foundation of the connection with mass of object, velocity and the pressure of the impact point provides the basis and experimental data with wave motion, AE forecast equipment and the evaluation of the fatigue strength. In this paper the problem of the progation of wave in a plate is studied by ansysing the wave form receiving from AE.Wave motion in a plate is an importment question for discussion in the field of wave vibration, its study affects the progress of acoustic emission testing in the field of nondestructive testing. The following work are done from the angle of AE signal testing:1. The following problems are ansysized by the acoustic emission orientation of defects experiment: the sources of noises, how to truly set parameter, how to operate standardly and how to avoid sources of noises and so on. The precision of AE orientation is improved. Orientation of defects comes true by receiving wave form, and it is very importment to analyse wave form and distinguish real wave.2. Firstly, the problem of progation of wave in plate with a hole is studied by using the methods of complex function, finding that: the DSCF of plate with a hole in vercital is about 1. 5 under the low frequency incident wave, in this case, the DSCF is smaller when the wave number becomes larger. And the frequency of incident wave is single, not considering dispersion. In this experiment the signal is directly received by AE, then the incident wave is obtained. Actually the frequency of incident wave is about 150KHZ in AE testing of mostly metal materials, so the influence of hole is not large in AE testing. 3. The connection with AE signal, velocity of object, and the pressure of the impact point is built by experiment and finite element method, this provides basis for the exploitation of AE forecast set and the evaluation of the fatigue strength after impacting.