Analysis of superplastic blow-forming in a conical closed die. (English) Zbl 0968.74506
Summary: A mathematical model using the finite-difference method has been proposed in this work to examine the plastic deformation behavior of the sheet during blow-forming in a conical closed die. In the formulation of this mathematical model, nonuniform thinning in the free bulged region and the contact condition including the sticking and sliding friction modes between the sheet and die are considered. Effects of various forming parameters such as the die entry radius, friction coefficient, inclined angle of the die, etc., upon the optimized pressurization profile, forming time and the thickness distribution of products were discussed systematically. Furthermore, experiments on superplastic blow-forming in a conical closed die were carried out using 8090 Al-Li sheets. It is found that the theoretical predictions agree with experimental results. The thickness distributions of the SPF-ed product obtained with different friction coefficients along the die entry, sidewall and bottom are closer to the experimental data than those obtained with a constant friction coefficient.
MSC:
74C15 | Large-strain, rate-independent theories of plasticity (including nonlinear plasticity) |
74S20 | Finite difference methods applied to problems in solid mechanics |
74-05 | Experimental work for problems pertaining to mechanics of deformable solids |