Interaction Influence of Flaw and Stress on L_cr Wave Acoustoelastic Coefficient of Carbon Steel

Abstract

Based on Lcr wave acoustoelastic theory, the influence mechanism of blind-hole on stress evaluation with Lcr wave was discussed. Combined with equivalent method, the blind-holes with different diameters were preset, the difference in time of flight between Lcr wave was calculated by cross correlation coefficient function, the Lcr wave acoustoelastic coefficient was determined with linear fitting function, the influence mechanism of blind-hole diameter on Lcr wave acoustoelastic coefficient was clarified based on the elastic plastic deformation theory and stress concentration theory of hole. The results show that when the diameter of blind-hole is different, the change rule of the difference in time of flight between Lcr wave is basically the same as stress increases, the difference in time of flight between Lcr wave increases linearly as stress increases, while the nonlinear feature is also gradually obvious, the maximum stress in linear stage is less than the yield strength of specimen, the Lcr wave acoustoelastic coefficient decreases gradually as blind-hole diameter increases, and it tends to be constant. The analysis shows that the stress concentration is seen as the main reason for above results, anisotropic structure of specimen and blind-hole depth are also the important reasons for that.

Keywords

• L_cr wave acoustoelastic theory
• stress concentration
• nondestructive evaluation
• elastic plastic deformation
• interaction influence