Интерпретация данных эксперимента по газовой формовке сплава АМг6 для определения условий его сверхпластичности
The paper presents a simple technique for the characterization of materials superplasticity by free bulging tests, which is based on inverse analysis. The main idea of this technique is a semianalytical solution of the direct problem instead of finite element simulation which allows one to reduce the calculation time significantly. Presented method use experimental time-thickness and time-dome height of the workpiece dependancies as initial experimental data. Presented method has been applied for AZ31 magnesium alloy at 520. Received properties have been veracity via simulation by finite element method. Obtained time-height relations were comparison with the data presented in the literature.
Determination of material constants describing its behavior during superplastic gas forming is the main subject of this study. The main feature of free bulging tests is the stress-strain conditions which are very similar to ones occurring in the most of gas forming processes. On the other hand, the interpretation of the results of such tests is a complicated procedure. The paper presents a simple technique for the characterization of materials superplasticity by free bulging tests, which is based on inverse analysis. The main idea of this technique is a semianalytical solution of the direct problem instead of finite element simulation which allows one to reduce the calculation time significantly. At the same time the results this simplified solution are accurate enough to obtain realistic material constants.
Free bulging process is an experimental technique which can be used to characterize a sheet material in conditions of biaxial tension during hot forming. Analytical and semi-analytical models of this process are usually based on the hypothesis offering certain relations between the geometrical characteristics of a bulge during forming. The paper presents an original relation between a specimen thickness at the dome pole and the dome height which is used at the semi-analytical method for simulation of free bulging process. In order to obtain this relation, the finite-element computer simulation results were generalized. The influence of the material constants on the geometrical parameters of the bulge was studied. It was shown that the sheet thickness corresponding to a specific dome height is dictated by the strain rate sensitivity index of the material. The equation describing the influence of the strain rate sensitivity index on the dome apex thickness is presented.
This work is devoted to the investigation of the thickness-height dependence of the freely molded dome. The series of simulations were produced by finite element method. The generalization of the simulation results allowed us to obtain an analytical thickness-height relation of the dome