The Study On The Ultrasonic Testing Of Stress And Its Visualization

As one of practical methods of non-destructive testing (NDT), ultrasonic testing is widely used in various departments of industry. Visualization in scientific computing (VISC) is one of the new applications of computer technology. VISC is an combination of computer graphics, image manipulation, computer vision, CAD, computing geometry, user interface and etc. This dissertation mainly associates ultrasonic NDT with VISC technology.Stresses in materials or components are inevitable for many engineering structures when they are manufactured or used. The reliability and life of the components or structures always depend on the stresses in the components. As the complexity of source and distribution of stresses, people can not at present control stresses, or even say nothing of using it efficiently. The measurement of stress can provide basis for material's evaluation, predict the fatigue life of the workpiece, inspect the technical effect of heat treatment and strength disposal on the surface, control cutting technics and determine the effect of stress elimination. Therefore, the effect measurement of stress is one of the most important tasks in engineering.In view of the requirement of stress testing in the engineering practice, based on the achievement in ultrasonic NDT and VISC, this dissertation investigates the detection of surface stress in several typical components using surface wave acoustoelasticity and its visual expression using VISC technology. The nonfiguratived data experimentally or theoretically obtained are converted to visual and idiographic figures, which are easy to understand and analyse.The dissertation is expected to lay a solid foundation for further investigation of ultrasonic stress measurement, visualization in data field, life evaluation and fatigue failure analysis of key components in structures.