A Study Of 6K21 Aluminum Alloy Sheet Deformation Behavior Under Tention And Shear Force

The case of aluminum alloy sheet deformation under tension and shear force often occurs in cars, ships and other collisions. In addition, sheet metal forming process, sometimes, because of the force complex situation, often two or three composite to the load. The case of aluminum alloy sheet deformation under tension and shear force is common in sheet metal forming process. However, previous domestic studies on the deformation behavior of aluminum alloy sheet in tension and shear forces are rarely. As a representative of six series aluminum, 6k21 aluminum is commonly used in the manufacture of automobile panel. This paper from the point of lacking to study the tensile and shear deformation behavior through self-transformed device, design 6k21 aluminum-shaped sample, and exert force to its horizontal and vertical direction, so that the middle region is under complex deformation with tension and shear load to study the material deformation behavior.Butterflied experimental samples simulated by finite element analysis software for different rolling angle a =0 °、45 ° and 90 °, and different load paths b = 90 °、75 °、60 °、45 ° and 30° to obtained the stress- strain curves varied in vertical direction. A marked material anisotropy appeared in simulation results. Besides, with the decrease of b(increase the proportion of horizontal shear force), the stress- strain curve quickly moved to the lower left of the Cartesian coordinate system.Using the self-transformed bi-linear load test device to exert tensile and shear force to 6k21 like above simulation path. A marked material anisotropy appeared in test results. Besides, with the decrease of b, the stress- strain curve quickly moved to the lower left of the Cartesian coordinate system. At the same, the trial’s yield strength, tensile strength, strength coefficient, hardening index decreases rapidly as b decrease. Test results are consistent with the simulation results, which demonstrate the simulation results are credible.Based on the data obtained in the experiment, compared the theory yield locus with the experimental yield locus in different rolling direction, butterfly-shaped specimen was found in a state of tension and shear stress state under tensile and shear force. And experimental yield locus is in the fourth quadrant in 1 2s -s principal stress spaces. The yield point is closest to Barlat yield locus which always describe aluminum’s anisotropic yield criterion.The rotation effect is obvious in large deformation, if ignored the effect of the rotation which will produce ignored strain, the measurement of strain is inaccurate, even false. Great rotation of local area prone to appear in tension and shear deformation.The decomposition theorem is firstly applied in this article to describe the large deformation of plate, and compared with the Cauchy strain tensor and Green strain tensor, which commonly used in the strain calculation. The experiment shows the accuracy in the calculation of large deformation of the decomposition theorem.