Finite Element Simulation with Coupled Thermo-Mechanical Analysis of Superplastic Dieless Tube Drawing Considering Strain Rate Sensitivity

Abstract

The deformation behavior in superplastic dieless tube drawing is studied numerically by the finite element method (FEM). The FEM with coupled thermo-mechanical analysis is conducted considering strain rate sensitivity to clarify the effect of dieless tube drawing conditions such as tensile speed and material properties on the deformation behavior of the tube. In the calculation, the material properties were dealt with as a function of temperature in a special subroutine, whose constitutive equation considering strain rate sensitivity and strain hardening was used, and was linked to the solver. FEM results for both heat transfer and the deformation profile are in good agreement with experimental results. Therefore, the validity of FE modeling of superplastic dieless drawing is demonstrated. In addition, the effect of material properties m and n values on the deformation profile is demonstrated numerically. As a result, a higher m value constrains the local instability deformation. In cases where the m value is high, the n value has little effect on the deformation profile. Consequently, it is found that analysis considering strain rate sensitivity is important for the prediction of the deformation profile in the dieless drawing process.