Papers by Author: D.M. Goudar

Abstract: Residual stress measurement techniques using mechanical strain relaxation depend on a number of physical quantities and are therefore sensitive to errors associated with the measured data. The resulting stress uncertainties can easily become significant and compromise the usefulness of the results or lead to misinterpretation of the behaviour of the residual stress distributions. It is therefore essential to develop an error analysis procedure for the measurements undertaken. Error analysis procedures for the deep hole drilling (DHD) method are developed to consider triaxial residual stresses. A modified deep hole drilling method, called the incremental deep-hole drilling (iDHD), was applied to measure the near yield residual stress distributions in a cold water quenched aluminium 7010 alloy forged block. The experimental results are used to illustrate the errors.

Abstract: In common with all mechanical strain relief residual stress measurement methods, extra care must be taken when making measurements on components containing highly triaxial residual stress fields which are close to yield. The introduction of a free surface, created as part of the measurement procedure, can lead to plastic redistribution of the residual stress field. Usually, this is not accounted for in the elastic inversion algorithms of the experimental procedure. This paper demon­strates the usefulness and accuracy of deep-hole drilling (DHD) method [1] in a component predicted to contain a triaxial residual stress field. Previous measurements [2] are compared with the results of a DHD simulation on a type 316H stainless steel pipe containing a repair weld offset from an original girth weld. The influence of different material models was also studied.

Abstract: This paper examines the extent to which mechanical shot peening (MSP), ultrasonic impact treatment (UIT) and laser shock peening (LSP) can affect the tensile residual stresses in the fusion zone caused by welding for a 10mm multi-pass 'V' groove weld within a 20 mm thick 304L stainless steel plate. Stresses are measured by deep hole drilling, neutron diffraction and incremental center hole drilling. For the UIT and LSP treated samples, the tensile stresses present in the as-welded plate are reversed to compressive stresses to a depth in excess of 2-4mm. For MSP the affected depth is much less (~0.5mm). The depth of these compressive stresses is similar to those measured in 20 mm thick parent plate test coupons.