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1 Journal of Achievements in Materials and Manufacturing Engineering

1 2007

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A management on mesh modelling for finite element analysis in casting simulation

Cho C., Kim W., Choi B., Kwak S., Pan Q.

Journal of Achievements in Materials and Manufacturing Engineering

2007

Vol. 20, nr 1-2

335-338

Purpose: In this paper we present a finite element mesh management technique applied to analyze thermal stress distribution of mushy region including molten materials and solidifying shell. Design/methodology/approach: In this study we terminated and eliminated the finite elements representing molten materials on the element list. When they became cooler than the liquidus temperature, the deleted elements were recreated. Findings: We considered temperature-dependent material properties during simulation and adopted hybrid FDM/FEM method for enhancing accuracy: We validated the proposed technique by comparing with other methods. As results, the proposed method is found to effectively simulate real-time casting process. Research limitations/implications: The resulting simulation of conventional methods should induce errors on estimating residual stress of the cast subjected to non-uniform cooling. For the stress analysis study of casting process before complete solidification, we introduce a special technique to treat molten parts in the numerical procedure. This study proposes a method reducing by several orders the elastic modulus of molten material through employing a reduction factor. Practical implications: Conventional casting process simulations don't consider stress due to complex rheological behavior of molten metals until the cast completely solidifies. Achieving uniform cooling rate in a whole cast body while solidifying must be an ideal casting process to avoid undesirable thermal distortion and stress in product which may induce hot tear and crack. Conventionally many prototyping tests should be conducted to this end and necessitate expensive costs. Originality/value: In this study we propose a new technique of "Element Creation and Termination" which terminates (or removes) molten elements and creates them just after they cool down to lower than liquidus temperature. Notice that the previous methods do not remove but deactivate molten elements.