Abstract:
As part of a programme investigating the structural integrity of welds, the
Digital Image Correlation (DIC)technique was used to obtain the full-field
strain distribution during tensile testing of cross-weld specimens cutfrom a
multi-pass girth welded pipe. The displacement maps were analyzed using Matlab
scripts to compute localstress-strain variations from which the local proof
stress values were extracted. It has been found that the DICparameters, such as
the size of interrogation windows (subsets) and speckle sizes, have significant
effects on the displacement values due to the local variations in the mechanical
properties within the weld between the passes.The DIC parameters were therefore
optimized using monolithic aluminium alloy specimens with stressconcentrations
giving similar displacement gradients. The use of a high resolution camera at
high magnificationallowed the variations between the welding passes to be
observed. The variation of the mechanical properties inthe weld region is
correlated with the full field hardness maps of the same region.
