Buxton, Ashley; Ahmed, Jasmin; Smith, Adam; Rowley, Robert; Kingstedt, Owen; Berke, Ryan (Utah State University)
Faculty Advisor: Berke, Ryan (College of Engineering, Menanical and Aerospace Engineering Department)
As nuclear facilities grow older, the Department of Energy (DOE) seeks to understand how materials degrade under irradiation conditions. However, engineering-scale radioactive specimens are expensive to irradiate and difficult to handle. Thus, there is significant interest in new methods to characterize materials using miniaturized specimens. In recent years, several promising techniques have gained popularity (for example: nano-indentation, MEMs-based micro-tension, or nano-pillar compression), but there remains a significant gap in translating measurements at a micro- or nano-scale to material properties at an engineering scale.
In the late stages of ductility testing, localized necking means that two specimens of the same material but differing dimensions can produce drastically different elongation measurements. Barba's Law addresses this through scaling relationships. The law's key assumption is that similarly sized tensile specimens develop geometrically similar necked regions. The presented work utilizes this relationship to bridge ductility tests across length scales.
Throughout this research, full-field displacements are measured using Digital Image Correlation (DIC). In brief, DIC works by recording images of a specimen before and after deformation with a digital camera, then comparing the images to compute deformation. The gauge region is then varied to assess whether Barba's Law can be satisfied with a single long specimen and multiple shorter gauge regions. Multiple physical specimen lengths are then measured to validate the DIC results.