# Creep-force – creepage relationship

## Introduction

The main calculation program CALC can model the connection between wheel and rail in many different ways. This tutorial shows you how to create curves of the creep-force – creepage relationship for the different couplings.

All models in this tutorial comprises three axles: axl_111, axl_112, axl_113 and axl_114, which all are running along the track at a constant speed of 10[m/s].

Pitch rotation of axle axl_111 is controlled by equation "func operp axl_111.vk= -Vo/ro_ - 0.25 * time". I.e. the longitudinal creepage in the contact point will start at zero and increase linearly. Creating a curve of the longitudinal creep-force – creepage relationship.

Angle of attack of axle axl_112 is controlled by equation "func operp axl_112.p= 0.1 * time". I.e. the lateral creepage in the contact point will start at zero and increase linearly. Creating a curve of the lateral creep-force – creepage relationship.

Yaw speed of axle axl_113 is controlled by equation "func operp axl_113.vp= -16 * time" and "func operp axl_113.vx= -12 * time". I.e. the spin creepage on right wheel will start at zero and increase linearly. Creating a curve of the lateral creep-force – spin creepage relationship.

Wheelset axl_114 also tests pure creepage. In this case the spin is created because of conical wheels.

• List the contents of the tar-file with command: tar -tvzk -f pure_creep.tgz
• Extract the contents of the tar-file with command: tar -xvzk -f pure_creep.tgz

## Cases in the runf-directory

The tutorial comprises the following files:
 File Name Wheel/rail-coupling Remark pure_creep_pe0.tsimf func wr_coupl_pe0 pure_creep_pe0-.tsimf func wr_coupl_pe0 Negative speed pure_creep_pe0_mumod.tsimf func wr_coupl_pe0 Considerations are taken to change of friction coefficient due to the slip speed pure_creep_pe3.tsimf func wr_coupl_pe3 pure_creep_pe3-.tsimf func wr_coupl_pe3 Negative speed pure_creep_pe3_mumod.tsimf func wr_coupl_pe3 Considerations are taken to change of friction coefficient due to the slip speed pure_creep_pe4.tsimf func wr_coupl_pe4 pure_creep_pe4-.tsimf func wr_coupl_pe4 Negative speed pure_creep_pr3.tsimf func wr_coupl_pr3 pure_creep_pr3-.tsimf func wr_coupl_pr3 Negative speed pure_creep_pr3_mumod.tsimf func wr_coupl_pr3 Considerations are taken to change of friction coefficient due to the slip speed pure_creep_pra3.tsimf func wr_coupl_pra3 pure_creep_pra3-.tsimf func wr_coupl_pra3 Negative speed pure_creep_fasim_1.tsimf coupl creep_fasim_1 pure_creep_fasim_1-.tsimf coupl creep_fasim_1 Negative speed pure_creep_fasim_1_mumod.tsimf coupl wr_coupl_fasim_1 Considerations are taken to change of friction coefficient due to the slip speed pure_creep_lookuptable_1.tsimf coupl creep_lookuptable_1 pure_creep_lookuptable_1-.tsimf coupl creep_lookuptable_1 Negative speed pure_creep_tanel_springs_1.tsimf coupl creep_tanel_springs_1

Run the files manually one by one, or execute script run_all.bat to execute all cases automatically.

## Create the creep-force – creepage relationships

All above cases will be plotted in the same diagram with file mplotf/pure_creep.mplotf.

Start the plotting activity by marking file mplotf/pure_creep.mplotf and select run with your right mouse button.

In the command options popup menu leave the ident fields empty, because all idents are already defined in the file.