After a wide ranging phase I program of experimental and theoretical studies, a combination of magnetic techniques has been identified with the best balance of technical performance and practical potential for biaxial stress determination in ferritics weldments. The work has included some seminal theoretical modelling of the interaction of magnetic fields with depth-dependent tensor stresses.
In addition to further background research relating to calibration and optimisation, the phase II work programme is developing a demonstrator system for testing on a range of industrial problems.
THE CAPABILITY TO PROVIDE NON-INVASIVE AND PRACTICAL IN-SERVICE MEASUREMENTS OF ABSOLUTE STRESS IN WELDED STRUCTURES HAS BEEN IDENTIFIED AS A KEY ELEMENT IN FITNESS-FOR-PURPOSE AND OTHER ANALYSIS, AND THE AVAILABILITY OF SUCH A METHOD WOULD PROVIDE SUBSTANTIAL ECONOMIC AND SAFETY BENEFITS. THE FIRST PART OF THE FOUR YEAR PROGRAMME PROPOSED WILL EXTEND BASIC UNDERSTANDING OF THE LIMITED NUMBER OF METHODS IDENTIFIED BY A RECENTLY COMPLETED STATE-OF-THE-ART REVIEW AS HAVING POTENTIAL FOR SUBSTANTIAL IMPROVEMENTS ON EXISTING APPROACHES. THIS WORK WILL BE CONCENTRATED ON MAGNETIC AND ULTRASONIC TECHNIQUES.
THE INITIAL OBJECTIVES WILL BE TO DEMONSTRATE THE MEASUREMENT OF CHANGES IN STRESS BOTH IN THE SURFACE AND BULK OF MATERIALS, FOR EXAMPLE PRIOR TO AND AFTER POST-WELD HEAT TREATMENT, FIT UP STRESSES ETC. FURTHER DEVELOPMENT WILL ENSUE TO MEASURE RESIDUAL STRESS IN THE SURFACE AND BULK OF THE WELDED STRUCTURES.
FOLLOWING COMPARISON OF THE METHODS AT THE MID-TERM REVIEW, THE FINAL STAGE OF THE PROGRAMME WILL DEVELOP THE BEST METHOD TO THE EXPERIMENTAL PROTOTYPE STAGE. SUCCESSFUL DEVELOPMENT WILL PROVIDE SUBSTANTIAL BENEFITS TO A WIDE RANGE OF EUROPEAN INDUSTRIES, BUT AT THIS STAGE THE WORK IS BEING LED BY THE OFFSHORE INDUSTRY AND PARTICULAR EMPHASIS WILL BE GIVEN TO OFFSHORE REQUIREMENTS.
Funding SchemeCSC - Cost-sharing contracts
20090 Segrate Milano