Abstract：Method of experiment and data processing using digital speckle correlation method to investigate sheet’s anisotropy was systematically introduced, then the anisotropy and its evolution of SPCC steel sheet and AA6061 aluminum sheet were researched. The results show that: the speckle strain measuring method is an effective tool to obtain the mechanical properties of sheets, whose greatest advantage is its capability to capture the whole strain field during deformation, and this is key to study mechanical properties of materials under complex loading conditions; for the SPCC steel sheet, the anisotropy of flow stress is not distinct, while the total and incremental Lankford coefficient (r values and r′ values) show obvious anisotropy, moreover its values decrease with the increasing of deformation, which is different with the constant Lankford coefficient by traditional strain measuring using extensometer; for the AA6061 aluminum sheet, the anisotropy of flow stress and r value are not obvious, however, the elongations of specimens in different directions to rolling show an distinct anisotropy, and the working hardening rate of flow stress and r′ value appear a sharp fluctuation when the true tensile strain is between 0.15 and 0.20; the anisotropy of the two sheet’s strain increases gradually with the increasing of deformation, especially for SPCC steel sheet.
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