Simulation of manufacturing processes in product development

Abstract: In the manufacture of aero engine components, three key manufacturing processes can be identified. These are welding, heat treatment and mechanical cutting. Depending on what is required in terms of mechanical- and geometrical properties in the final product these processes are typically combined in a certain sequence. It is consistently these three processes, and the modelling and simulation of them using the finite element method, that are of concern to the work presented in this thesis. Product development phases such as the detailed design phase and the process planning phase are typically simulation intensive in aerospace industry. Normally, both more extensive component and manufacturing process data are available at these stages compared to in the previous concept development phase. It is however becoming increasingly important to enable predictions of manufacturability to be made early in the product development process. Changes made in the manufacturing process chart after a product offer is released will result in an increase in cost and a decrease in profit of that component. The aim of the work presented here is thus to develop strategies and computational technologies suitable for simulation of manufacturing processes in early stages of product development. An example of a computational technology developed in this work is the method of element deactivation used to simulate distortion effects of mechanical cutting. Within the area of simulation of manufacturing processes most research work and most publications focus on one individual process being simulated. This has been of great importance for the evolution of computational methods and analysis tools used both in industry and academia. However, when the focus of using simulations often is to determine process parameters in order to obtain desired product properties in the final product, it is essential to include the entire manufacturing process sequence in these simulations. In order to enable a sequence of manufacturing processes to be simulated, engineering information data need to be transferred between simulations of the individual processes. A system for engineering information data exchange in the context of manufacturing simulations is presented in this work. An approach commonly used for concept generation is knowledge based engineering (KBE). In KBE-systems, rules are implemented that embodies the enterprises’ product- and process knowledge. In this thesis, an integrated system where mechanical cutting simulations are performed within a knowledge based engineering software framework is presented. The thesis also deals with friction modelling in the rotary friction welding process and what is appropriate, in terms of computational matters, when attempting to simulate friction welding in a concept development context. The main theme in the thesis is thus to develop strategies, methods and computational technologies suitable for simulation of manufacturing processes such as rotary friction welding and mechanical cutting in early stages of product development.