Volker Landersheim

Applications for a new production technology – analysis of linear flow-split linear guides

Within the collaborative research centre 666 “Integral Sheet Metal Design with Higher Order Bifurcations” the innovative manufacturing technologies linear flow-splitting and linear bend-splitting are researched that allow the continuous production of multi-chambered steel profiles in integral style. The massive forming processes create an ultra-fine grained microstructure in the forming area that is characterized by an increased hardness and lower surface roughness compared to as received material. These properties predestine the technology to be used in the production of linear guides. Additionally, the multi-chambered structure of the linear flow-split and -bend components can be used for function integration. To design and evaluate linear guides that use the whole technological potential, the research is focused on a macroscopic and a microscopic point of view.The macroscopic approach is targeting the development of linear flow-split linear guides with integrated functions to provide additional performance values to the established machine parts. Continuously produced guidance systems with innovative functionality can be introduced to a new market with the technology push approach. Preliminary designs of linear flow-split guidance systems and integrated functions are promising. Therefore, an approach to develop new functions for linear flow-split linear guides basing on calculation models and property networks is shown [1]. With this approach, optimized solutions can be created and possible design modifications can be derived. In this contribution, the development and integration of a clamping function for decelerating the slide is presented. Calculation models for analyzing the functionality are presented and validated by finite element models and experiments.The microscopic examination of the profiles aims to investigate the material behavior, particularly of the formed areas. Beside the conventional mechanical and fatigue properties of linear flow-split material ZStE500 [2], the present work focuses on the rolling contact fatigue. This is necessary to evaluate linear flow-split components regarding their eligibility with regard to the rolling contact fatigue behaviour. The Hertz theory for rolling contact fatigue is only valid for homogeneous materials [3]. The flow-split material ZStE500 shows a non-homogeneous behaviour and has to be analyzed with the Finite Element Method in order to determine stresses and strains. In comparison to simulation results with unformed and therefore homogeneous material, the effect of linear flow-split surfaces on the rolling contact behavior is demonstrated. Based on these results, it is possible to start experimental investigations on rolling contact fatigue of linear flow-split components to validate the FE model and determine the performance of linear flow-split flanges for rolling contact fatigue.Copyright

Numerical fatigue strength evaluation of inhomogeneous, linear Flow Split Profiles

The innovative sheet metal forming technology “Linear Flow Splitting” offers various new options for designing profile-like components. The forming process leads to severe changes in local material properties, inhomogeneities and residual stresses within the manufactured component. These effects influence the mechanical properties of the manufactured components. If the components are designed to endure cyclic mechanical loads, it is especially important to know the components fatigue properties. This paper focuses on a method to derive the fatigue properties of Linear Flow Split Profiles by nonlinear numerical FE analysis, including durability analysis and forming simulations. This numerical approach offers the possibility to estimate the fatigue properties of components before manufacturing physical prototypes, only based on material parameters derived from tests on smooth samples. The Finite-Element analysis of the Linear Flow Splitting Process provides distributions of local material deformation and residual stresses. These results are mapped by an appropriate interface on FE models, which allow simulating the component behavior under external loads. Thus, the inhomogeneous elastic-plastic material behavior and residual stresses are considered in the computed stresses and strains. Further on, a post-processing tool was implemented to interpret the FE results considering the inhomogeneous distribution of materials fatigue properties, the mean stress distribution and the statistical size effect.Copyright

Ontology-Based Approach to Transform Fatigue Properties of Branched Sheet Metal Products for Use in Algorithm-Based Product Development

In order to shorten the design process of a multi-chambered profile, it is important to integrate the Technological Findings of the production and the evaluation of the manufactured product in a structured and systematic way, providing mathematical optimization. The development of profiles exposed to cyclic mechanical loading has to take into consideration their fatigue properties. This paper proposes a classification structure of the existing Technological Findings of Linear Flow Splitting and the continuous manufacturing line. The classification is realized by an ontology, modeling the manufacturing processes, machines, the geometry of the semi-finished product, sub-processes, engaged machine components and specific conditions for the employed material. A profile manufactured by linear flow splitting is subject to severe changes of local material properties. This affects the fatigue properties of the profile. The paper focuses on preparing the integration of these fatigue properties in a simplified approach into the mathematical optimization. The approach is developed by modeling examples of profiles with different material properties by methods of mathematical optimization. The examples are applied to a numerical fatigue evaluation. Results and conclusions drawn of this analysis are incorporated in the ontology as data and rules, serving as an input for the optimization.Copyright