PREDICTION OF EARING IN TEXTURED ALUMINIUM SHEETS BASED ON CRYSTAL PLASTICITY

<正> The phenomenon of earing is investigated in the present study based on the theory of crystalplasticity with the dynamic explicit finite element program developed.Firstly texture analysis is carried out ofrolled aluminium alloy Al5052 by means of X-ray technique.Then from the texture coefficients an analyticalexpression for the orientation distribution function(ODF)is derived making use of the computer algebraiclanguage Mathematica4.0,which makes it easier to discretize the ODF into a series of Eulerian angles repre-senting the distribution of lattices and further the preferred orientation (texture) of crystals of the original she-ets.For the polycrystal model,the material is described using crystal plasticity where each material point inthe sheet is assumed to be a polycrystalline aggregate of a very large number of face-centered cubic (FCC)grains with each grain modelled as an FCC crystal with 12 distinct slip systems.The modified Taylor theoryof crystal plasticity is used and only the initial texture is taken into consideration during large plastic deforma-tion.Numerical simulation of earing has been performed for an aluminium sheet with texture and one withcrystals exhibiting random distribution to demonstrate the effect of texture of materials on their plastie anisot-mpy and formability.