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The substructure file wr_coupl_pra1.ins

The model of the track in substructure file wr_coupl_pra1.ins is built up in a very similar way as the substructure file wr_coupl_pr1.ins. The main difference between wr_coupl_pr1.ins and wr_coupl_pra1.ins is that instead of using a lookup table as in file wr_coupl_pr1.ins, file wr_coupl_pra1.ins calculates the creep forces according to Kalker's simplified theory.

In substructure file wr_coupl_pra1.ins the wear of wheels and rails are calculated according to Archard's wear model:

Vwear = Volume of wear [m3]
k = Wear coefficient [1]
N = Normal force [N]
s = The sliding distance [m]
H = The hardness of the softer material [N/m2]

The wear coefficient k is not constant for all sliding speeds and contact pressures, because different regions have different kind of wear mechanisms. The wear coefficient k is defined in a wear chart.

Example: analyse_wr_coupl_pra3_wear_chart_example.gif

In addition to the required input data variable names in wr_coupl_pr1.ins above, substructure file wr_coupl_pra1.ins also requires the following variables:

H = Hardness in Vickers N/m2
Arch_speed_borders = Speeds, separating the different regions in the wear chart
Arch_press_borders = Pressures separating different regions of the wear chart
Arch_wear_coeff = Wear coefficients for the different wear regions in the wear chart

The code of the substructure can be read in the file $gensys/calc/insert_files/wr_coupl_pra1.ins

The input and output parameters are defined under command func wr_coupl_pra1