In Tdyn RamSeries, static non-linear analysis also allows the study of structures that have membranes and cables. For those scenarios, it is not mandatory for the analysis to be a dynamic one. An Incremental load analysis can be defined if the applied loads are static.
In these cases (membranes, cables or even very thin sheets), the stiffness matrix may be ill-conditioned or singular. In general, for dynamic analyses, this ill-conditioning should not pose any convergence issue, as the damping compensates for the stiffness matrix singularity. However, for incremental nonlinear cases, convergence problems may appear due to a lack of damping. To overcome this inconvenience, Tdyn-RamSeries has implemented a method that adds a numerical stabilisation (that is, an artificial damping).
This artificial damping is given by the diagonal matrix SFM (Stability Factor Matrix), using a Stabilisation Factor. Once the number of increments defined by the user are finished, Tdyn RamSeries performs an extra amount of increments (Stabilisation Increment Number) to guarantee analysis stabilisation and the required convergence.