From macro- to micro-experiments: Specimen-size independent identification of plasticity and fracture properties

The stress-strain response of most engineering materials can be conveniently determined using well-established macro-specimens with outer dimensions several millimeters or even centimeters. However, in the case curved thin-walled structures spatial material property gradients, it is often impossible to extract macro-specimens. For first group specimen are greater than structural dimensions, while for second group, assumption statistically-homogeneous properties not valid throughout a volume as large gage section. A frequently encountered example gradients around welds metallic castings automotive engineering. In view characterizing local plasticity and fracture at millimeter scale, micro-testing technique discussed this study. addition, microscopic experimental results 100?m thick steel alloy API X52 compared standard macroscopic counterparts 2mm thickness. new custom-made device employed load uniaxial tension, notched, central hole in-plane shear micro-specimens quasi-static nominal actuator strain rate less 1?m/s. These micro-scale experiments on pipeline performed under an optical microscope; planar digital image correlation used compute surface fields. initiation model then derived conventional macro- micro-experiments. It concluded that provides powerful means characterize whose homogeneous over few hundred microns only.