Rolling Stock > Structural Model > RM-Model

Definition of the structural system to be analyzed. The tool allows for analyzing some standard types of bridge structures and up to a certain size also models specified in the analysis program RM. The actual type of the structure to be analyzed is selected in the pull-down menu of the input field Model Type.

Setting	Description
RM Model	The structural data are taken over from the database of an RM project. Some relevant governing parameters such as ramp lengths and damping constants can in addition be entered in this input pad.
PROJECT	Data governing the take-over of the structural data of the RM project
Path	Directory, where the RM project has been established
Schedule	Relevant schedule variant for taking over the data
Loadcase	Name of the load case containing the relevant mass specification Note: The mass definitions must essentially be prepared in the RM project
Node Serie (1-6)	Definition of up to 6 series of nodes loaded simultaneously by the axle load (distribution of the axle load on up to 6 longitudinal girders) In longitudinal direction, the nodes of the superstructure must have been continuously numbered in RM with constant step.
RM Set for result nodes	This RM Set must be defined in the RM project and contain the nodes to be considered for calculating the vertical accelerations and building the acceleration envelope. Maximum 39 nodes allowable for consideration!

Analysis-Model

Additional structural data for describing the dynamic behavior

Setting	Description
Begin ramp	Length of the region, where a load becomes gradually effective at the first node while it approaches the begin of the bridge. This avoids the consideration of sudden impacts causing unrealistic results.
End ramp	Length of the region, where a load gradually looses its effect on the last node after it has left the bridge structure. This avoids the consideration of sudden impacts causing unrealistic results.
Damping	The damping parameters are taken from the RM project database. I.e. the relevant parameters alfa and beta have to be entered there correctly. (Menu Recalc > Dynamic). Note: The program uses Rayleigh damping, where the damping matrix is a linear combination of the stiffness matrix and the mass matrix (C = alphaM + betaK). In this approach, the equivalent damping ratio is varying with the frequency. The coefficients alpha and beta are calculated in the program such that the given damping ratio is exact for the angular frequencies w1 and w2 (in rad/s). Modes with frequencies between these values are slightly less damped, those with frequencies outside this region are damped to a higher extent.