An automatic CAE tool for autonomous feasibility assessment of aluminium gravity die castings : development and calibration

• Ein automatisches CAE-Werkzeug für die autonome Machbarkeitsbewertung von Aluminium-Schwerkraftkokillengussteilen : Entwicklung und Kalibrierung

Schopen, Marcus; Bührig-Polaczek, Andreas (Thesis advisor); Bähr, Rüdiger (Thesis advisor)

Aachen : Gießerei-Institut der RWTH Aachen (2022)
Book, Dissertation / PhD Thesis

In: Ergebnisse aus Forschung und Entwicklung 32
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2022

Abstract

In-service performance of cast parts (strength, crash, durability) not only depends on part design but also on manufacturing effects like gating and feeders (size, location), cast part orientation in the mold, and process parameters (filling rates, pouring and mold temperatures). In the conventional, computer-aided engineering (CAE) approach, casting experts manually set up and evaluate the feasibility of an actual design variant based on the engineering specification and quality requirements of the customer. Consequently, the number of design iterations is limited. In next-generation development processes, fully automated CAE tools and expert systems are required to provide a feasibility and quality evaluation for multidisciplinary design optimization (MDO) tools as well as design engineers in early design phases. This thesis describes the development and calibration of such a fully integrated, highly efficient and predictive Automatic CAE Tool to provide directional results for the application to lightweight chassis parts (gravity casting, A356). It defines gating and feeder design and initial process conditions, runs simplified casting simulations and quantitatively evaluates the cast part based on customer specifications (investigated metrics: filling success, microstructure and shrinkage porosity). This new approach does not require any manual user intervention of a casting expert. Additionally, a significant calculation time reduction by 90% is achieved by evaluating the filling success based on an implemented innovative analytical method. Furthermore, a systematic calibration method is developed and applied to calibrate and validate the Automatic CAE Tool. Two sets of experimental castings with different complexity are produced at various pouring and mold temperature levels: the standard fluidity spiral and a newly developed demonstrator part with different design elements characteristic of industrial chassis parts. In the last step, a CAE study demonstrates the plausibility and sensitivity of the estimated results. In sum, the Automatic CAE Tool has proven to be capable of providing a fast and efficient casting feasibility evaluation in the development of high-quality lightweight cast part designs. Therefore, it represents an important building block for fully analysis-driven design optimization methods including automatic setup and decision-making and delivers quantitative results, provided the effort is made to develop a specific calibration and validation database. The accuracy of its results may be further improved if a physically based, efficient method is developed for the remaining key issues of casting process simulation (gap dependent heat transfer coefficients, gas porosity).

Institutions

• Division of Materials Science and Engineering [520000]
• Chair for Foundry Science and Foundry Institute [526110]