Establishment of a 3D FE model for the bending of a titanium alloy tube

Establishing and developing a finite element (FE) model is key to the effective study of the complex bending of a titanium alloy tube. This paper focuses on the establishment of a three-dimensional (3D) FE model for the numerically controlled (NC) bending of a titanium alloy tube that considers both bending and springback. The key procedures for establishment of the model are described in detail, including the choice of elements, mesh density control, the choice of single- or double-precision computation, and the choice of the mass scaling factor. Combining explicit and implicit FE methods, a significant amount of springback can be modeled for the bending, which is in good agreement with what is observed in practice. Single-precision computation tends to provide increasingly inadequate results as the mass scaling factor decreases. Analyses performed using double-precision computation can improve the accuracy of the results. A decrease in the mass scaling factor when double-precision computation is used leads to improved results to some degree, but also to an increase in computation time. Taking accuracy and efficiency into consideration, a mass scaling factor of 1600 is considered reasonable. Using our 3D FE model, results for the distributions and variations of the tangential stress, tangential strain, wall thickness, and springback angle for the bending of a TA18 M tube were obtained.