Solidification in castings by finite element method

A self-contained CAD (computer aided design) system capable of analyzing foundry casting processes in sand and gravity dies is being developed at the University College of Swansea. The work involves preprocessing, postprocessing, and a finite element code with some novel numerical techniques. The solidification of castings is a heat transfer problem involving phase change, which may occur in a narrow range of temperatures. To simulate the phenomena accurately, very fine meshes must be used and the solution of such a system becomes very expensive. In the Swansea system, an adaptive remeshing technique is introduced, which tracks the moving front of the phase change zone. At every time step, a scan is made to determine the points at which phase change is occurring, so that the remeshing may be done to produce a refined mesh at such points. The computing process is then continued. Examples have illustrated that the method is efficient and accurate. In addition, an interfacial heat transfer model is introduced to improve the simulation of the casting process. Advective heat transfer in the liquid is also modelled. © 1990 The Institute of Metals.