Elastoplastic Buckling of Anisotropic Aluminum Plate Elements

In the current paper, the effect of plastic anisotropy on the elastoplastic buckling behavior of individual outstand plate elements is investigated. The elastoplastic plate-buckling problem is very sensitive to modeling parameters, and there is still some discrepancy between tested and simulated results. Stress-strain behavior and R-values have been measured by performing uniaxial tension tests in different directions in extruded plates of aluminum alloy 7108, temper T7. Several anisotropic yield criteria, found in the literature, have been calibrated in different ways, using both initial yield-stress values and R-values. An explicit finite element code, LS-Dyna3D, has been used to study the effect of plastic anisotropy on plate buckling. The yield criteria are evaluated for this particular problem. A special rig for testing of individual outstand elements has been designed, and plates of different width-thickness ratio have been tested. The tested plates have been compared with the results from the numer...