Minimum time-step size for diffusion problem in FEM analysis

In this paper oscillation of results arising from the use of a time-step size which is less than the minimum required is examined. The phenomenon is summarised to give two requirements that the solution of boundary problems has to satisfy. An approach to derive the minimum time-step size for various kinds of elements is developed. A theoretical veriÞcation is presented for the one-dimensional two-noded element case and a numerical examination of the criteria explored for the two-dimensional eight-noded element case