An Ultrasonic Computerized Complex (UCC) for residual stress measurement was developed recently in a joint project between Integrity Testing Laboratory Inc. and Ukrainian scientists. The UCC includes a measurement unit with supporting software and a laptop with an advanced database and an Expert System for analysis of the influence of residual stresses on the fatigue life of welded elements. The Complex allows one to determine uni- and biiaxial applied and residual stresses for a wide range of materials and structures. In addition, the developed Expert System (ES) can be used for calculation of the effect of measured residual stresses on the fatigue life of structural elements, depending on the mechanical properties of the materials used, type of structural elements and parameters of cyclic loading.
The supporting software allows one to control the measurement process, to store the ultrasonic measurement data, to calculate and draw the distribution of residual stresses. The software allows the use of the designed method and equipment with standard PC’s.
Using the ES, it is possible to assess, through calculations, the influence of the residual stresses and their redistribution under the effect of various improvement treatments and cyclic loading on the service life of structural components without having to perform time- and labor-consuming fatigue tests. The program package enables one to calculate the fatigue life of structural components after application of heat-treatment, vibration treatment, overloading, UP and other improvement treatments.