In the calculation parameters of RFEM 5 and RSTAB 8, the text boxes Number of load increments for load cases/load combinations are available under the Global Calculation Parameters tab. These two entries control the numerical incremental application of the defined load boundary conditions in the respective load cases and load combinations. The reciprocal value of the entry describes a fraction of the load. The solving process then applies the defined load fractions successively to the model in load increments until the complete load is reached. In den einzelnen Laststufen versucht der Gleichungslöser im Rahmen der maximal erlaubten Iterationen ein Gleichgewicht zu finden und damit passenden Startwerte für die nächste Laststufe vorzugeben.
It is possible to imagine that the solving process collects the complete load of a load case or a load combination in a "watering can" and pours it onto the load-collecting model in portions. In this case, the number of load increments correlates to the speed of the load application. The speed is not to be understood as a real-time parameter, but purely numerically.
Important: The incremental load application only has an effect in the case of nonlinear structural systems. It usually provides a correspondingly higher result quality with an increasing number of load increments. The basic aim of this method is to find a micro-convergence in the respective load increments to specify new high-quality start values for the next load increment, and thus finally to achieve a macro-convergence for the entire load case.
