Sound Elastic Effects Within The Test Metal Material Plane Stress

The acoustoelastic phenomenon not only as a technique for experimental stress analysis but also as a nondestructive technique for evaluation in metals, which can be used to evaluate metals all period from be made up to serve, has been extensively attracting related research people domestically and abroad.The present paper has generalized and summarizes the acoustoelastic theory in the plane stress. It has studied the temperature influence to LY12 aluminum alloy. In this paper, This self-developed a set of four-point bending loading fixture, and two sets of transducers holder, it is showed that four-point bending fixture comply with design requirements, the experimental phenomenon of stability, one of which transducers holder works well, stable and reliable experimental data.Shear wave velocity changes as the polarization angle (or rotation angle of sensor) changes in unstressed condition;The results indicate that when the oscillation direction of the shear wave makes an angle of about 60 degrees or 120 degrees with rolling direction, the shear wave velocity decreases sharply and the relationship between shear wave velocity and rotation angle tends to become discontinuous in LY12 aluminum alloy; When the oscillation of the shear waves occurs in the anisotropic direction of the rolling direction, the shear wave velocity exhibits a peak value; After researching to LY12 aluminum alloy, can conclude that maybe the Microcosmic Preferred Orientation cause the shear wave velocity cups.In this paper, it is consistent with that the present paper deals with the classical acoustoelasticity in plane stressed and elastically deform media when they are submitted bending stresses. Numerical and experimental evaluations of the resulting change in the ultrasound velocities as a function of bending loads are described. Through detecting the shear wave velocity of different polarization direction in unstressed condition, obtained that the LY12 aluminum alloy and 45 steel sample are the characteristics of orthotropic materials, ie, they had fast axis and slow axis of shear wave velocity, which have an Characteristic that the lower velocity transverse the faster velocity.It detected the plane stress under four-point bending in LY12 aluminum alloy and 45 steel samples by acoustoelastic method, comparing the detecting result with the Computation simulation by the finite element, the acoustic elasticity detecting and the analogue result tallies well in the magnitude. But partial test point's result in 45 steel and the simulation value had discrepancies, maybe because the anisotropic of 45 steel and the modeling selection of finite element software, this is worth further studying. Ultrasonic birefringence phenomena under four-point bending and its application are studied in this paper. In the following work, the relationship between ultrasonic velocities and the applied stress under two dimensions tensile or compression will be futher studied; the stress evaluation by ultrasonics will be studied and will be applied to pratical production. So, stress determination by ultrasonics has a broad application.