Ultrasonic Technique and Device for Residual Stress Measurement

One of the advantages of ultrasonic techniques for residual stress measurement is that they are non-destructive. Using such techniques, one can measure the residual stresses in the same points many times, studying, for instance, the changes of re-sidual stresses under the action of service loading or effectiveness of stress-relieving techniques. An Ultrasonic Computerized Complex (UCC) for non-destructive measurement of residual and applied stresses was developed recently. The UCC includes a measurement unit with transducers and basic supporting software and an advanced database and an Expert System, housed in a laptop, for analysis of the influence of residual stresses on the fatigue life of welded elements. In general, the ul-trasonic method allows one to measure the residual stresses in both cases: averaged through thickness or in surface layers. The present version of UCC allows measuring the averaged through thickness residual stresses in plates 2- 150 mm thick. The advanced ultrasonic method, the equipment and some examples of residual stress measurement are discussed in this paper