Handling of Discontinuities

Since for both ODEs and DAEs Simcenter Amesim methods are used, the question of discontinuities must be addressed. In all standard Simcenter Amesim component models rigorous discontinuity handling is employed. If there is a discontinuity in a state variable or its 1st or 2nd derivative, the method described in Methods for Differential Algebraic Equations is used to locate the discontinuity and restart the integrator. If the discontinuity occurs at a known time, this can be done very rapidly. In other cases interpolation is used to find the discontinuity point.

For users who write there own models, the manual tutorial exercises and training courses stress the importance of proper discontinuity handling. To make the process easier, a collection of simple to use utilities are available which are called from within the user’s model.