A Measurement of Bauschinger Effect of Thin Sheets Based on Reverse Simple Shear Deformation and Digital Speckle Correlation

Simple shear tests for the SPCC (steel plate cold-rolled commercial) and AA6061 aluminium alloy sheets were performed with a three dimensional digital speckle correlation strain measuring system, and the Bauschinger effect under strain path reversal condition was tested. The results show that it is easy to achieve reverse loading and obtain the mechanical properties at large deformation by simple shear deformation. The digital speckle correlation is a good method to capture the whole strain field, and makes sure that the measurement of shear strain is exact. The shear stress versus shear strain curves for both materials at different pre-strains show a good agreement. Reversed yield stress increases with the increase of pre-strain. By comparing the experimental and predicted results, the evident Bauschinger effect and transient effect exist for both materials, while the SPCC steel shows rather obvious permanent softening effect.