As it was announced in the call, the metal-based additive process (SLM) as innovative manufacturing technique should be used for the environment-friendly production of components and modules of the advanced GTF demonstrator and therefore to meet the requirements of the SAGE 4 concerning a fuel burn reduction combined with a decrease in noise emission. For compliance with the high requirements of the aerospace industry, concerning the process stability and part quality of the SLM process, numerous rigs testing are required to integrate the manufactured parts in a SAGE 4 full engine. As described in the call, high resource consumption is necessary if the process qualification is performed directly at the manufacturing system. This includes the increased material usage, the personnel deployment and a decreased system availability. A significant reduction of the production efficiency is the result and is in contrast to the requirements of SAGE 4.
Hence, the main objective of this proposal was to develop a simulation tool that is based on an integrated finite element model by considering the material properties and process parameters of the manufacturing process for a realistic mapping of aerospace parts of the GTF. Thus, for every part that had to be manufactured, the virtual process qualification of SLM increases the quality objectives “high density", “reduced distortion and residual stresses” and “specified microstructure characteristics”. Due to the development of user-specific optimisation methods that were based on the simulation results, a significant economisation of resources for the manufacturing process was reached within the project work and thereby the requirements of the SAGE4 with regard to the advanced GTF demonstrator was fulfilled.
Laser Beam Melting is an additive manufacturing (AM, often referred to as “3D-printing”) process that allows the production of full dense metal parts. The build-up is done layer by layer enabling the production of almost arbitrarily complex geometries. Therefore, Laser Beam Melting exhibits a significant advantage compared to conventional machining where manufacturing costs typically increase with the part’s geometrical complexity. As a result, experts expect the market for systems, services and materials for AM to quadruple in the next 10 years. The simulation tool developed within the research project AeroSim strives to contribute to improve the Technology Readiness Level (TRL) of Additive Manufacturing and particularly Laser Beam Melting.
Metal-based additive manufacturing processes can be used for the environment-friendly production of light weight aero engine components. However, high standards concerning the process stability and the resulting part quality need to be fulfilled. Today, the part specific process of identifying a set of process parameters and design, which lead to the fulfilment of the given quality standard, is often conducted by manufacturing test samples. Thereby, different objective criteria (e. g. minimised distortions) should be improved by means of adjusting the process parameter configuration. These experiments are not enhancing the final product value but lead to a higher material usage, a high staff allocation and a decreased system availability. In May 2012, the Institute for Machine Tools and Industrial Management (iwb) of the Technische Universitaet Muenchenstarted AeroSim with the aim of developing a simulation tool for Aero Engine applications.
The main objective of the research project was the development of a numerical model that was able to predict resulting part properties with a high accuracy in order to replace the manufacturing of samples and to allow for a virtual quality control. By modelling material properties, process parameters and ambient influences, the prediction of temperature fields, residual stress and distortion occurring in the produced part is possible. To achieve a high performance level of the simulation system (sufficient result accuracy within shortest possible calculation time) suitable abstraction methods were developed. For example, efficient meshing algorithms for mapping complex part geometries as well as abstractions concerning the heat input had been investigated. In addition, the desired software tool contains an optimization-algorithm and a GUI, which provided intuitively understandable visualisation of the simulation results and can be used without profound expertise in simulation and programming.
On the microscale level, process phenomena (e. g. melt pool dynamics) can be investigated by utilizing the process model. For analysing resulting residual stress states or distortions of built parts, a macroscale model of the build process was developed. The validity of abstractions on the macroscale are derived from investigations on the microscale by utilizing the process model. To guarantee maximum user benefit, suitable interfaces, also with the additive manufacturing machine, were developed. Furthermore, the simulation models were connected to a user-friendly optimization system. The considered materials within AeroSim are nickel-base super alloy Inconel 718 and titanium-base alloy Ti-6Al-4V.