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In this paper, a three-dimensional elasto-thermoviscoplastic finite element method using tetrahedral MINI-element is established. We extend the related theories from the three-dimensional rigid-thermoviscoplastic finite element method based on the tetrahedral MINI-element to the three-dimensional elasto-thermoviscoplastic finite element method. Some details about the related theories and numerical schemes are introduced with typical application examples including a homogeneous compress of solid cylinder and an automatic five-stage cold forging process of automobile part of yoke. The former showed its validity and the latter exhibited its applicability. [ABSTRACT FROM AUTHOR]

In this paper, elastic, rigid-viscoplastic and elastoplastic finite element analyses of typical metal forming processes or structural problems of multi-body cases occurring in metal forming are conducted to present their mechanical characteristics together with validation of the numerical approaches. Theoretical backgrounds are briefly introduced with an emphasis on the contact condition treatment of moving or deformable bodies. The application problems in metal forming are classified into three categories namely typical multi-deformable body case, mechanically coupled case between material and dies and bonded material group case. Mechanics of overloaded ball bearing problem, typical assembling processes, coupled material and dies problem, bolt-and-nut assembling process, composite material forming, and structural analysis problem of assembled die are solved. The predictions are discussed to validate their accuracy and to extract valuable engineering insights. [ABSTRACT FROM AUTHOR]

In this paper, finite element analysis of a rotary forging process is conducted for an assembly process of hub bearing assembly unit (HBAU) by rotary forging with an emphasis on the residual stress of bearing parts as well as the structural parts. A theoretical analysis model is given, based on rate-independent assumption of the material to minimize the numerical effect. An elastoplastic finite element method with MINI-tetrahedral elements is employed. The multi-body function is employed to prevent the predictions from being numerically affected by the interface treatment scheme. Two inner races of duplex pair taper-roller bearings as well as the hub shaft are treated as elastoplastic materials. To remove the numerical effects of convergence and volume consistency on the finite element prediction, which may occur during near-idling rotational motion of materials, the material is fixed while the relative tool velocities are maintained. The predictions are discussed to reveal the characteristics of the assembly process. It is to be noted that the cavity between the hub shaft and the bearing inner race could be predicted and that it generated two distinctly separable normal stresses around the bearing race shoulder, which are related to the anti-play stress between the two parts and the joining stress of the duplex pair bearing races. [ABSTRACT FROM AUTHOR]