Full Field Strain Measurements in Welds.
SOUTH CAROLINA UNIV COLUMBIA
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The intent of this study is to examine the stress-strain response of small material subsets in a weld subjected to some nominal loading using a full-field surface strain mapping technique. This process makes use of the digital image correlation program VIC2D developed by the University of South Carolina. Full-Field surface strain mapping will be used to help determine the basic material properties of the various regions within a weld, which are the heat-affected zone and the mechanically affected zone weld nugget. During development of this process, various specimens were tested to verify the accuracy of the strain mapping procedure. A tapered stainless steel tensile specimen was studied and the results verified by a finite element model of the test specimen. The results from the full-field strain mapping matched very closely with the strain distribution predicted by the finite element model. To further prove the validity of the strain mapping process, a .0135 inch diameter hole was drilled in a 5454-0 aluminum tensile specimen. The strain measurement process detected the perturbations in the strain field caused by the defect at displacements as low as three-hundredths of an inch within the three-inch gage length. Furthermore, the strain measured near the edge of the specimen using the mapping technique matched to within .01 the strain measured by an extensometer attached to the test specimen.
- Couplers, Fasteners and Joints