Comparison of experimental and theoretical residual stresses in welds: The issue of gauge volume

Welding residual stresses have an effect on many aspects of the integrity of structures but are normally one of the largest unknown stresses. Residual stresses are difficult to measure and to estimate theoretically but are often significant when compared with the service stresses on which they superimpose. High tensile residual stresses can lead to loss of performance in corrosion, fatigue and fracture.In this research, measurement of residual stresses by the neutron diffraction technique is compared to an analysis of a sample geometry by theoretical finite-element procedures. The results indicate good qualitative agreement. One of the key issues in this comparison relates to what is termed “gauge volume” in the measurement technologies and what might be described as a “calculation volume” in theoretical approaches.