An experimental approach for determining the effect of machining the gage section of specimens for quasi-static, biaxial tension/shear testing of sheet steels is described. This method is demonstrated by comparing the results found by an existing testing method with a reduced thickness (Mohr and Oswald Exp Mech 48:65-77, 2008) to that of full-thickness specimens. Finally, the same results are compared to a specimen in which half of the thickness is removed. These tests are performed on DP780, a first generation advanced high-strength steel. Analysis of the full-thickness and one of the reduced thickness specimens shows that some second-order effects in measuring stress occur from these procedures, but these effects are small. Direct comparison of the engineering stress versus strain curves for the tested conditions shows that for the steel under consideration, there is little dependence on full-thickness, partial thickness, or through-thickness sampling location for continuum-level anisotropic plasticity properties in multi-axial loading for the material investigated and the methods used in manufacturing the specimens.
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