16 Repeatability of Contour Method Residual Stress Measurements for a Range of Material, Process, and Geometry 105 Fig. 16.4 Stainless steel forging dimensions and measurement location (dimensions in mm) measurement provided a 2D map of residual stress. All measurements were performed in a consistent manner to assess measurement repeatability. The following is a brief description of the measurements performed on each set of specimens. For the aluminum T-section specimens, contour method measurements were performed at the mid-length of ten specimens (127 mm (5 in) from each end, as shown in Fig. 16.1). Six titanium welded specimens were measured at the plate mid-length, as shown in Fig. 16.3. The contour method measurements on the stainless steel forgings were performed at the specimen midwidth (shown in Fig. 16.4) for six specimens. For the six nickel alloy (half) disk specimens, contour method measurements were performed at the specimen mid-width (shown in Fig. 16.5). Stress release from sectioning the disks in half was found using a supplemental stress analysis in conjunction with the strain change recorded before and after sectioning (using strain gages at multiple locations). The total hoop stress, including the effect of sectioning, is reported for the disk specimens. The stainless steel DM weld repeatability study consisted of measurements at different positions along the length of the plate, rather than making measurements in nominally identical specimens removed from the long plate. This was done to preserve the original residual stress field present in the plate, which is more representative of a highly constrained weld employed at pressurized water reactor (PWR) nuclear power plants. The repeatability experiment consisted of five contour method measurements, where each measurement repeatedly cut the plate in half. Figure 16.2 show that the first measurement (Cut 1) cut the plate in half; the second (Cut 2A) and third measurements (Cut 2B) cut each of the half plates in half; and the fourth (Cut 3A) and fifth measurements (Cut 3B) cut two of the quarter plates in half. Corrections were made to account for the small changes in residual stress as the specimen size was reduced by previous contour measurements. The corrections used the data from prior contour method measurements at the subsequence measurement plane was as done in [7].
RkJQdWJsaXNoZXIy MTMzNzEzMQ==