This work shows a sequence of numerical models for the simulation of the Presta joining process: a well-established industrial process for manufacturing assembled camshafts. The operation is divided into two sub-steps: the rolling of the shaft to widen the cam seat and the joining of the cam onto the shaft. When manufactured, the connection is tested randomly by loading it with a static torque. Subsequently, there are three numerical models using the finite element method. Additionally, a material model of finite strain viscoplasticity with nonlinear kinematic hardening is used throughout the whole simulation process, which allows a realistic representation of the material behavior even for large deformations. In addition, it enables a transfer of the deformation history and of the internal stresses between different submodels. This work also shows the required parameter identification and the associated material tests. After comparing the numerical results with experimental studies of the manufacturing process for steel-steel connections, the models are used to extend the joining process to the utilization of aluminum shafts.

Considerable weight benefits and the option to combine various steel alloys of the single parts are the major advantages of assembled over conventional camshafts. The Presta joining process is the leading manufacturing method of assembled camshafts in the global market. The process is divided into two substeps. At first, the outer diameter of the shaft is widened with a profile oriented orthogonal to the shaft axis at the intended cam seat. At this position the shaft is subsequently joined with a cam with an internal profile oriented parallel to the shaft axis. As a result, these perpendicular profiles form a tight fit due to plastic deformations. Consequently the simulation of the manufacturing process has to start with the simulation of the rolling of the shaft. The resulting profile requested in this step is axisymmetric, but the arrangement of tools is not. Thus a three-dimensional model is required, which is presented in this work. Furthermore, the infeed of the rolling tool is unknown and controlled by the stiffness of the holders of the rolling tool. This work shows the modeling of this behavior. To predict realistic results for the underlying process, the use of precise material models is essential in order to take several hardening mechanisms into account. However, the use of complex material models implies additional effort, which is shown in this work.

The Presta joining process is based on the separate manufacturing of internal profiled cams and shafts with previously widened diameters at the intended cam seat through rolling. With regard to further optimization and enhancement, the two substeps are modelled and simulated using FEM. The results of the rolling process simulation are employed as the starting point for the simulation of the joining step, which is presented in this contribution. First, the shaft is widened with a profile oriented orthogonal to the shaft axis at the intended cam seat. Subsequently, the shaft is joined with a cam that has an internal profile oriented parallel to the shaft axis. Due to plastic deformations these perpendicular profiles form a tight fit. Because of these complex plastic deformations, that are related to large local forming degrees, the use of precise material models is essential. Moreover, it is necessary to maintain the deformation history of the rolling simulation in the joining step with regard to effects like kinematic or isotropic hardening. For that purpose, the applied material model's invariance under change of the reference configuration is used by transferring its internal state variables from one simulation step to another. Finally, the results of the simulation are compared to measurements of series production.

This work deals with the modelling and simulation of curing phenomena in adhesively bonded piezo metal composites which consist of an adhesive layer with integrated piezoelectric module and two surrounding metal sheet layers. In a first step, a general modelling framework is proposed which is able to represent curing phenomena in polymers at finite strains. Based on this formulation, a concretized model is deduced for the simulation of curing in one specific epoxy based adhesive. Here, appropriate material functions are specified and the thermodynamic consistency is proved. Regarding the finite element implementation, a numerical integration scheme and a new approach for the consideration of different initial conditions are provided. Finally, finite element simulations of a newly proposed manufacturing process for the production of bonded piezo metal composite structures are conducted. A deep drawing process of the composite with uncured adhesive layer and the subsequent adhesive curing are investigated.