Developing Cruciform Specimen Geometries for Warm and Elevated Temperature Biaxial Testing

摘要

With the increasing interest in controlled biaxial testing, as the more accurate representation of loading cases the material experiences during sheet metal forming operations, there is a vital need for cruciform specimen geometries that can accumulate large and uniform biaxial plastic strains within their gauge areas. This is particularly crucial for lightweight materials, in view of their great potentials and steadily-increasing share in sheet metal forming applications. This investigation aims at developing viable cruciform geometries, particularly suited for warm and elevated temperature biaxial testing of lightweight alloys. A balanced biaxial testing apparatus is used to deform a variety of AZ31B magnesium cruciform specimens up to fracture. Strain maps of the deformed specimens are constructed by digital image correlation, and they are used to validate the viability of each design, based on the extent of deformation biaxiality and its ability to promote uniform plastic strains within its gauge.