Finite-Element analysis of a rolling contact model with anisotropic elastic material properties

Die elastischen Eigenschaften eines Werkstoffs sind ein wichtiger Parameter für das Design und die Dimensionierung von Struktur- und Funktionsbauteilen, in Bezug auf die Steifigkeit, des Rückfederverhaltens und die Ermüdungseigenschaften. Die vorliegende Arbeit befasst sich mit der Auswirkung der elastischen Anisotropie auf die Eigenschaften im Wälzkontakt eines hochgradig umgeformten ferritischen Stahls. Lineare Profile, welche mit dem neu entwickelten Umformverfahren des Spaltprofilierens hergestellt wurden, eignen sich aufgrund ihrer geringeren Oberflächenrauigkeit und der gesteigerten Oberflächenhärte besonders für die Anwendung als Linearführung. Texturdaten aus EBSD Messungen dienen der Berechnung der elastischen Tensoren der stark umgeformten Bereiche der Profile anhand des geometrischen Mittels, zusätzlich zu den klassischen Ansätzen nach Voigt und Reuss. Die hergestellten Profile weisen eine starke elastische Anisotropie in der Ebene parallel zur Wälzkontaktoberfläche auf. Die Ermittlung der Wälzkontakteigenschaften der umgeformten Mikrostruktur erfolgte durch die Implementierung der zuvor berechneten Nachgiebigkeitstensoren in ein FE Wälzkontaktmodell. Zur analytischen Verifikation nach Hertz, wurden die Ergebnisse in Relation zu homogenen und isotropen Materialeigenschaften gesetzt und konnten unter Berücksichtigung des von Mises Versagenskriteriums bewertet werden

Manufacturing Induced Properties: Determination, Understanding, and Beneficial Use

Based on its procedural principle, every manufacturing technology affects a variety of properties of the workpiece or product in a characteristic way (Sect. 2.3). The sum of all those properties which comprise geometrical as well as material-related ones is considered as manufacturing-induced properties. While the geometric manufacturing-induced properties are often the reason why a specific technology is chosen by the designer for the manufacturing of a certain product, the material-related manufacturing-induced properties are often seen as by-products of the process. With regard to metal forming, all manufacturing processes inherently influence the mechanical properties of the manufactured material. In many cases, these mechanical manufacturing-induced properties are merely regarded in terms of restrictions in product development. However, with respect to a manufacturing-integrated product development approach, the mechanical properties are of special interest, since we aim at utilizing their full potential to maximize the product performance

The Result: A New Design Paradigm

One of the key challenges faced by engineers is finding, concretizing, and optimizing solutions for a specific technical problem in the context of requirements and constraints (Pahl et al. 2007). Depending on the technical problem’s nature, specifically designed products and processes can be its solution with product and processes depending on each other. Although products are usually modeled within the context of their function, consideration of the product’s life cycle processes is also essential for design. Processes of the product’s life cycle concern realization of the product (e.g., manufacturing processes), processes that are realized with the help of the product itself (e.g., use processes) and processes at the end of the product’s life cycle (recycling or disposal). Yet, not just product requirements have to be considered during product development, as requirements regarding product life cycle processes need to be taken into account, too. Provision for manufacturing process requirements plays an important role in realizing the product’s manufacturability, quality, costs, and availability (Chap. 3). Further life cycle demands, such as reliability, durability, robustness, and safety, result in additional product and life cycle process requirements. Consequently, the engineer’s task of finding optimal product and process solutions to solve a technical problem or to fulfill a customer need is characterized by high complexity, which has to be handled appropriately (Chaps. 5 and 6)