Plastic deformation of ultra-thin pure titanium sheet subject to tension-compression loadings

Measurement of the Bauschinger effect of ultra-thin metallic sheet by the conventional tension-compression (TC) test is challenging due to the premature buckling during compression. In this study, a test method based on a multi-layered sandwich specimen is newly introduced to suppress the buckling in the uniaxial compression. Theoretical calibration is conducted for obtaining accurate flow stress under compression by correcting the effects of adhesive and friction induced by supporting side plates. Also, strains during the TC tests are measured by the digital image correlation (DIC) technique. From the proposed TC test with the sandwich specimen, plastic deformation of 0.1-mm-thick ultra-thin pure titanium sheet was investigated under reverse loading. Finally, the constitutive model based on the distortional hardening concept is newly developed and calibrated to reproduce the Bauschinger effect of the investigated ultra-thin sheet subject to TC loadings.