The project house will establish the Aachen Virtual Platform for Materials Processing, AixViPMaP for short, as an infrastructure providing computing power and software licenses and function as a service provider for external partners.
The abbreviation ICME is considered internationally to describe a new research approach for the development of materials and their processing and manufacturing processes. The term "Integrative Computational Materials Engineering" stands for the numerical simulation of long process chains across process stages and scales. In the Integrative Production Technology for High-Wage Countries Cluster of Excellence initiative Steel Institute IEHK, Metal Forming Institute IBF, Institute of Plastics Processing IKV, Geometry and Practical Mathematics IGPM, Laboratory for Machine Tools and Production Engineering WZL, Access e.V. and Fraunhofer Institute for Production Technology IPT jointly develop new materials and the associated process technology using this new method. With the "Aachen Virtual Platform for Materials Processing", AixViPMaP for short, a simulation platform has been developed that makes it possible to combine different simulation programs at different research centers into a virtual process chain.
Steel is by far the most widely used metallic material and is increasingly exposed to higher requirements. Bridges are expected to grow in size, vehicles not only lighter, but also safer, and wind turbines are being exposed to ever higher loads. At the same time, steel producers have to compete in a global market. Therefore, industry and science are faced with the task of finding an optimal relationship between required mechanical and functional properties as well as material and production costs. These properties depend on the chemical composition and thus on the raw materials. However, commodity prices are highly volatile in a global marketplace. In order to produce competitive components for the industry, particularly expensive alloying elements (such as nickel or molybdenum) are possibly replaced by less expensive substitution metals (for example manganese), whereby quality losses may not occur here. At the same time, production must continue to be cost-effective.
Pair software tools
AixViPMaP is a platform on which different software tools in the field of material and process simulation can be coupled efficiently and effectively. Against the background of producing tailor-made materials in cost-optimized production processes, the use of mathematical modeling methods is becoming increasingly important. Various computer programs or models on macro-, micro- and nanoscale are combined to illustrate the complex relationships in material development and production. The results of a process simulation serve as input parameters for subsequent simulations and thus the influence of the parameter change on the final properties of the component can be determined.
The functionality of AixViPMaP can be illustrated with gearboxes for wind turbines: transmissions are central parts of the wind turbine, which have to withstand high and difficult to predict loads. The risk of wear and failure is great. Especially in a wind farm in the sea far from the coast, such a wind turbine is exposed to enormous environmental influences and forces due to temperature changes and wind loads. Damage that must be repaired is intricate and expensive. The goal in the production of wind turbines is therefore to develop transmission components with the highest possible longevity or mileage and high resistance. At the same time, the total weight of the construction must remain limited. When designers develop transmissions for new wind turbines, an optimal material with high safety and at the same time the lowest possible alloying and production costs must be determined. Conventional case-hardening steels are often not enough or they are very expensive. Experience for alternative steels is missing. With the help of AixViPMaP platform, a new steel can be designed with adapted lifetime characteristics and optimized production costs for the respective application. The service life of transmission components depends on many factors. The basis for the production of such a steel is on the one hand the chemical composition, which makes the degree of purity crucial. The production consists of many process steps, starting with casting and solidification. The aim here is the most homogeneous distribution of the elements, so that the component has, for example, the required strength at all points. The subsequent forming steps such as forging and ring rolling serve to produce a blank, wherein the component is given its basic form. By a heat treatment, the machinability of the material for the subsequent machining is set. The so-called soft cutting produces by rotation the basic final geometry for the component and cuts the teeth out of the blank by hobbing. During carburizing, the component is heated in a carbon-rich atmosphere so that carbon can diffuse into the component via the surface. Subsequent quenching produces an outer layer of high hardness. At the same time, a ductile core is created which then provides the required elastic properties. Finally, the distortions that may have occurred during carburization are removed by grinding and the component is brought to its final high-precision geometry.Copyright: © Lukas Koschmieder
Learning through every simulation
These processes depend on each other in different ways and an optimization must take place over the entire process chain. With the help of AixViPMaP, the entire process chain is simulated on the macro, micro and nano level so that the process parameters can be set optimally for each process step. Subsequently, the predictions made are checked at the laboratory level by producing and testing the material in the laboratories of the RWTH partners. In principle, the model parameters for all process simulations are identified and determined. As part of the established simulation chain, which maps the entire industrial process chain, the data from the previous calculation serve as input for the next simulation. Thus, for example, the information about grain size, local residual stress or hardness can be monitored with each process step. In this way, a simulation chain for the calculation of tooth root bearing capacity - it says something about the lifetime of the component - is developed and validated by means of example toothing. Here, the institutes benefit from the fact that all process steps necessary for the production of gearwheels can be shown experimentally in the various RWTH laboratories. When using the simulation platform, the scientists work closely with industrial partners. In a current project, a new alloying and process concept for case hardening steel for large gearbox components with improved purity and thus lifetime in industrial practice is implemented. Among others, a steel producer, a forging company, a heat treatment company and an oven manufacturer are involved.