Применение обратного анализа для определения реологических констант материалов по результатам тестовых формовок круглых мембран
The paper is oriented toward the problem of determination of rheological characteristics of a material by free bulging testing. This information about the material behavior is used for design of gas forming technologies for production of complex shell parts used in aerospace industry. Realization of such technologies requires pressure forming regimes which can be calculated using computer simulation. The material model describing its behavior during hot forming is one of the most important inputs of the simulation. Tensile testing is the most popular way of investigation of the material behavior. A significant disadvantage of this method is that the material formed in conditions of uniaxial tension which is not similar to the one realized in gas forming technologies. Free bulging technique considered in the paper allows one to study the behavior of a material during hat forming in condition of biaxial tension. Inverse analysis utilizing a special semianalytical model for the direct task is used for interpretation of the results. The model is based on the differential equation describing the evolution of dome height using special relation for the calculation of specimen thickness at the dome pole. This approach was applied for the processing of experimental results obtained by forming of industrial aluminum alloys. The obtained material constants were also used in finite element simulation of bulging process by MSC.Nastran software in order to verify the efficiency of proposed technique. The results of the simulations were found to be in good agreement with the experimental data.