NUMERICAL-SIMULATION OF THE INTEGRAL HYDRO-BULGE FORMING OF NON-CLEARANCE DOUBLE-LAYER SPHERICAL VESSELS - ANALYSIS OF THE STRESS STATE

The integral hydro-bulge forming (IHBF) of non-clearance double-layer spherical vessels is simulated numerically by the explicit finite-elem ent code LS-DYNA3D. The stress distribution. the strain distribution a nd the residual stress are discussed in the present paper:. The numeri cal results show good agreement with experimental results. Bulging def ormation appears over most of the blank area; bending deformation occu rs near to the blank edges and blank corners (shell vertices of the in tersection area of weld seams), especially on the uncontacted areas of the outer shell, whilst high tensile stress exists at the inner surfa ce. The residual stress may be reduced to below 20% of the yield stres s of the material after bulging. (C) 1998 Elsevier Science S.A.