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BoBo-vehicle tutorial

This tutorial consists of the following steps:

• Start the filemanager program GENFILE
  
• Copy the example to your working directory
  
• Examine directory "intro_tutor_bobo"
  
• The vehicle
  
• View the vehicle in program RUNF_INFO
  
• View the vehicle in program GPLOT
  
• Perform a modal analysis of the vehicle
  
• Perform a modal analysis taking car-body structural flexibility into account
  
• Make a stability analysis on tangent track at 340[km/h].
  
• Find the non-linear critical speed of the vehicle.
  
• Make a simulation through a curve, without track irregularities.
  
• Make a simulation through a curve, with track irregularities and in-line post processing.
  

Start the filemanager program GENFILE

If the installation has been made for KDE or GNOME just click on the -icon on the desktop. On other systems open a terminal and write:  genfile 

If the genfile-window has been started via the -icon, the gensys filemanager will start in directory $HOME/analyse. In the title of the genfile-window you can see your location. The file managing program that now starts will be referred as the GENFILE- or GENSYS-window, and is described in more detail in the genfile users manual.

Copy the BoBo-example to your working directory

• Create a new and empty directory by writing
  mkdir tutor_bobo_test 
  in the "Command input area" of the genfile window.

• Go to the new directory by double-clicking the directory name, and press the  cd –pushbutton.

• Copy example files to the newly created directory. Please choose one of the following methods:
  • Pressing Help -> Examples Html in the gensys-window
  • Pressing Help -> Examples Filemanager in the gensys-window
  • Download the example via a tar-file from the Internet

Examine the directory "intro_tutor_bobo"

• Program GENFILE now shows the contents of directory intro_tutor_bobo.

• The input data files for program TSIM (time-domain simulation) is located in subdirectory runf.

• In order to see the contents of subdirectory runf double-click subdirectory runf, and all files in the runf-subdirectory will appear in the File area to the right.

• Open the master input data file for editing by double-clicking the runf/Master.runf-file and select open->op with the right mouse button in the window background menu.

The vehicle

The vehicle defined in file runf/Master.runf is a motor car with 2 bogies and 4-axles. The runf/Master.runf-file make calls to subfiles in the input data reading process, the subfiles are:

A detailed description of the runf/Master.runf-file with its sub-files can be found in Description of a rail road vehicle model.

Examine the vehicle in program RUNF_INFO

Program RUNF_INFO is a program which lists how masses and couplings in the model are linked together. Program RUNF_INFO is controlled by an input data file which is described in the RUNF_INFO users manual.

• Create an input data file for program RUNF_INFO

• Open and examine the newly created file by double-clicking the runf_infof-directory in the "Subdirectory Area".
  The "File Area" now shows the contents of the runf_infof-directory. Double-click the input data file in the "File Area" and select File -> Open from the pulldown menu.

• Execute program RUNF_INFO

• Program RUNF_INFO creates the following files:

  calc.out	=	Memory dump of all variables in the model
  diags/runf_info.ps	=	A two-dimensional plot, showing how all bodies connects to each other
  runf_infor/Master.runf_infor	=	An ASCII-file containing text information about the model

  Examine the files by double-clicking on them and select open->op with the right mouse button.

• The first graph in file diags/runf_info.ps:
  
  Horizontal boxes are masses.
  Vertical boxes are couplings.

The files calc.out, runf_infor/Master.runf_infor and diags/runf_info.ps can now be closed.

View the vehicle in program GPLOT

Program GPLOT is a graphic program showing a three dimensional view of the vehicle.
Start program GPLOT with the file runf/Master.runf by:

• Double-click directory runf/ in the subdirectory text field
• Double-click file runf/Master.runf in the file text field
• Press the  GPLOT –pushbutton

• Mouse button #1(left) zooms the model
• Mouse button #2(middle) rotates the model
• Mouse button #3(right) moves the model

If you zoom in to a bogie you can see that all couplings have a hot-spot. If you press the hot-spot with mouse button #1 you will get information of that specific coupling. Below is a close up of the first bogie of the vehicle:

Close the GPLOT-window, before continuing with the next section.

Perform a modal analysis of the vehicle

Program MODAL calculates all possible modes of vibration in the model. Number of modes are as many as the number of equations in the model. A low damped mechanical system of one degree of freedom has two complex conjugated eigenvalues. A high damped mechanical system of one degree of freedom has two real eigenvalues, both eigenvalues are negative. A self oscillating mechanical system is a system where the real part of the eigenvalue is positive.
Before the modal analysis starts, program MODAL linearizes the nonlinear equations by an amplitude defined in command modal_param.
Make a modal analysis of the vehicle:

• Copy the file runf/Master.runf to runf/modalRigid.modalf, by giving the command
  cp runf/Master.runf runf/modalRigid.modalf
  in the "Command Input Area".

• Open the new file by double-clicking on runf/modalRigid.modalf and select open->op with the right mouse button.

• Change line 19 from:

  func  const    vkmh= 160      # The initial speed of the vehicle in km/h
  

  To:

  func  const    vkmh= 250      # The initial speed of the vehicle in km/h
  

• In order to make sure that we have the correct contact forces between wheel and rail, it is advisable to use results from QUASI as initial values into program MODAL. Change line 94 from:

  #   pre_process=  'quasi $CURRENT_FILE'                                                                        
  

  To:

      pre_process=  'quasi $CURRENT_FILE'                                                                        
  

  
  Change lines 314-317 from:

  ##                                                                     
  ##      Read initial values from GPdat-file, generated by QUASI        
  ##      ==========================================================     
  #  if_then_char_init CalcType .eq. TSIM                                
  #              .or.  CalcType .eq. MODAL                               
  #   initval read_gpdat gp/$IDENT.gp 1                                  
  #  endif                                                               
  

  To:

  ##                                                                     
  ##      Read initial values from GPdat-file, generated by QUASI        
  ##      ==========================================================     
     if_then_char_init CalcType .eq. TSIM                                
                 .or.  CalcType .eq. MODAL                               
      initval read_gpdat gp/$IDENT.gp 1                                  
     endif                                                               
  

• Launch program MODAL by clicking Gensys -> Run Current File in the pulldown menu.

• A pop-up menu will appear in order to let you select different command line arguments. Start the job by clicking the OK-button.

• In the output from program MODAL you can see that a number of files has been created:

  calcmod/modalRigid.modjac		The Jacobian of the linearized system.
  calcmod/modalRigid.modf		ASCII-file containing the eigen forms
  calcmod/modalRigid.mode		ASCII-file containing the eigen values
  gp/modalRigid.gp		File written in GPdat-format for animation in program GPLOT.
  id/modalRigid.id		File written in MPdat-format for plotting of root-locus plots in program MPLOT.

• Open a file by double-clicking the file and select open->op with the right mouse button.
  N.B. You will notice that file id/modalRigid.id is unformatted. Instead of opening the file directly it will be filtered through program mp2ascii. A popup-menu will appear where you can choose how to translate file id/modalRigid.id.

• Start program GPLOT, by double-clicking file runf/modalRigid.modalf and press the  GPLOT –pushbutton.

• To read the eigenvalues and modal shapes into program GPLOT, select File->read_gpdat from the pulldown menu. Double-click file gp/modalRigid.gp.

• When program GPLOT has read the file gp/modalRigid.gp, a picture of mode #1 will be shown.

• Click on Deform->draw_deform in the pulldown menu, in order to see a list of all available eigen modes.

• Double-click mode number 6, which is the first mode of vibration having a relative damping less than 100%.

• Eigen modes 1 to 5 and 7 to 15, are highly damped eigen modes. If the damping of the mode exceeds 100% the mode does no longer have a harmonic solution, instead the eigen mode have an exponential solution.

• Eigen modes having a relative damping less than 100% are complex valued eigen modes. Each complex valued eigen modes consists of two complex conjugated value pairs. Where one of the modes has a positive eigen frequency and the other has a negative eigen frequency.
  In the Deform->draw_deform–menu only modes with a positive eigen frequency has been listed. You can see that all eigen modes with a negative eigen frequency has been removed from the list, for example mode 5, 16, 18, 21, , , etc.

• To start the animation, press the  Fwd –pushbutton in the lower left corner of the window.

• Eigenmodes can also be changed with the  Next  and  Prev  pushbuttons in the pull-down menu.

• An alternative way of starting program GPLOT with the modalRigid-model is to write the following command:
  gplot runf/modalRigid.modalf gp/modalRigid.gp &
  Now both files are read into GPLOT during its startup phase.

Show animation of the lower sway mode of the BoBo-vehicle:

Find the following mode shapes in the vehicle:

Close the GPLOT-window, before continuing with the next section.

Perform a modal analysis taking car-body structural flexibility into account

Results from a modal analysis in a FEM-program of a car-body at free-free conditions are stored in the subdirectory patranr. This example shows how to take car-body structural flexibility into account:

• Copy file runf/modalRigid.modalf into runf/gplot_id.modalf by giving the command:
  cp runf/modalRigid.modalf runf/gplot_id.modalf
  (If you not have the runf/modalRigid.modalf-file, please go to section Perform a modal analysis of the vehicle)

• Double-click file runf/gplot_id.modalf and select open->op with the right mouse button.

• Run program NPICK inside program MODAL by doing the following changes in file runf/gplot_id.modalf:
  
  Change the lines 92-93 from:

  #   pre_process=  'sed "s!runf/Master.runf!$CURRENT_FILE!" npickf/flex_car.npickf > npickf/$IDENT.npickf'  
  #   pre_process=  'npick npickf/$IDENT.npickf'                                                                
  

  To:

      pre_process=  'sed "s!runf/Master.runf!$CURRENT_FILE!" npickf/flex_car.npickf > npickf/$IDENT.npickf'  
      pre_process=  'npick npickf/$IDENT.npickf'                                                                
  

  
  In order to model the car-body as a flexible body in program QUASI and MODAL change the lines 307-309 from:

  ##                                                                     
  ##      Read flexible parameters for the carbody                       
  ##      ==========================================================     
  #  if_then_char_init CalcType .ne. NPICK                               
  #   insert file npickr/$IDENT.npickr                                   
  #  endif                                                               
  

  To:

  ##                                                                     
  ##      Read flexible parameters for the carbody                       
  ##      ==========================================================     
     if_then_char_init CalcType .ne. NPICK                               
      insert file npickr/$IDENT.npickr                                   
     endif                                                               
  

• Launch program MODAL by clicking Gensys -> Run Current File in the pulldown menu. Program NPICK and QUASI will automatically be executed within MODAL.

• If you open file calcmod/gplot_id.mode and compare its contents with file calcmod/modalRigid.mode, you can see that we now have got 6 more eigen modes. Since each equation of motion is a second order differential equation, it will lead to two new equations for each degree of freedom. The 6 new equations are named car_1.c1, car_1.c2, car_1.c3, car_1.v1, car_1.v2 and car_1.v3. Equation car_1.c1 tells us how much the first bending mode of the car-body is excited. Equation car_1.c2 tells us how much the torsional mode of the car-body is excited. Equation car_1.c3 tells us how much the second bending mode of the car-body is excited. The equations car_1.v1, car_1.v2 and car_1.v3 tells us the speed of the first bending mode, torsional mode and second bending mode, respectively.

• Start the GPLOT program, by writing:
  gplot runf/gplot_id.modalf gp/gplot_id.gp &

• In order to change eigenmode: click on Deform->draw_deform in the pulldown menu or press the  Next –pushbutton in the pull-down menu.

• In order to start the animation, press the  Fwd –pushbutton in the lower left corner of the window.

Show animation of the first bending mode of the car-body:

If you open the Deform->draw_deform popup menu. You will see that you have got 6 more eigen values, compared to the previous case modalRigid. These new equations arise from the three flexible modes added by program NPICK.

Find the following mode shapes in the vehicle:

Please close the GPLOT-window, before continuing with the next section.

Make a stability analysis on tangent track at 340[km/h].

• Copy file runf/Master.runf to runf/stab_340.tsimf by giving the following command:
  cp runf/Master.runf runf/stab_340.tsimf

• Open file runf/stab_340.tsimf and change the line 19 from:

  func const    vkmh=  160       # The initial speed of the vehicle in km/h     
  

  to:

  func const    vkmh=  340       # The initial speed of the vehicle in km/h     
  

  
  
  Change line 322 from:

  #  initval set_var  car_1.vp= .15
  

  to:

     initval set_var  car_1.vp= .15
  

• Launch program TSIM by clicking Gensys -> Run Current File in the pulldown menu.

• Animate the time-domain simulation in GPLOT:
  • Double-click file runf/stab_340.tsimf and press the  GPLOT –pushbutton
  • Select File->read_gpdat from the pulldown menu
  • Double-click the gp/stab_340.gp-file
  • Select View->show_1_diag
  • Set the Deformation scale fact equal to 25 approximately
  • Click the  Fwd –pushbutton
  • In order to step frame by frame in the animation, press the  Next – or  Prev –pushbutton in the pull-down menu.
  • Close the GPLOT-window

• Animate the time-domain simulation in GLPLOT:
  • Double-click file runf/stab_340.tsimf and press the  GLPLOT –pushbutton
  • Select File->read_gpdat from the pulldown menu
  • Double-click the gp/stab_340.gp-file
  • Click the  -> –pushbutton
  • In order to step frame by frame in the animation, press the  +1 – or  -1 –pushbutton in the pull-down menu.
  • Show animation in GLPLOT:
    
  • Close the GLPLOT-window

• Plot the results in MPLOT running in interactive mode:
  • Press the  MPLOT –pushbutton
  • Select File->open mpdat-file in the pulldown menu
  • Double-click the stab_340-ident
  • Select Draw->curve from current ident in the pulldown menu
  • Write axl_122 in the upper Text-Field, and press return
  • Double-click the axl_122.y variable, which is the lateral position of last axle of the vehicle
  • Write bog_12 in the upper Text-Field, and press return
  • Double-click the bog_12.y variable, which is the lateral position of the last axle of the vehicle
  • Write car_1 in the upper Text-Field, and press return
  • Double-click the car_1.y variable, which is the lateral position of the car-body

  • Press the  Undo –pushbutton or the Del-Key if you like to erase the last input
  • Press the  New –pushbutton if you like to start plotting in a new page and keep all curves in current page.
  • Press the  Edit –pushbutton if you like to change curves, grid, scales,,, etc.
    • The following example changes the scale of the X-axle:
    • In the new window change xint/cm= auto to xint/cm= 0.5
    • Save the file by pressing Ctrl+S
    • In the MPLOT-window click the  Reload –pushbutton
  • By clicking Draw->diagram # the drawing area can be divided into several smaller diagrams
  • The interactively generated plot:
    
  • Close the MPLOT-window

• Plot the results by MPLOT in batch mode:
  • In the file mplotf/stab_batch.mplotf the same plot is stored as a batch job
  • Double-click the file mplotf/stab_batch.mplotf and press Ctrl+R
  • Select mode of operation to batch
  • Set ident1 equal to stab_340 and press the  OK –-pushbutton
  • Answer  Replace  in the next pop-up window
  • Double-click file diags/stab_340.ps Select open->genrun with the right mouse button
  • Close the mgv-window

Find the non-linear critical speed of the vehicle.

• Copy file runf/Master.runf to runf/crit.tsimf by giving the following command:
  cp runf/Master.runf runf/crit.tsimf

• Open file runf/crit.tsimf and change the lines 19-20 from:

    func const  vkmh=  160               # The initial speed of the vehicle in km/h
  # func operp  vkmh=  450 - 5 * time    # Vary vkmh in order to calculate critical speed
  

  to:

  # func const  vkmh=  160               # The initial speed of the vehicle in km/h
    func operp  vkmh=  450 - 5 * time    # Vary vkmh in order to calculate critical speed
  

  
  
  Change lines 322-323 from:

  #  initval set_var  car_1.vp= .15
  #  force rel_lsys1  retard  car_1  0 0 -hccg*.6 -mvhe1*5/3.6 0. 0.  0. 0. 0.    # Apply redardation 5[km/h/s] as an external force
  

  to:

     initval set_var  car_1.vp= .15
     force rel_lsys1  retard  car_1  0 0 -hccg*.6 -mvhe1*5/3.6 0. 0.  0. 0. 0.    # Apply redardation 5[km/h/s] as an external force
  

  
  
  Change the line 328 from:

  tstop= 10.
  

  to:

  tstop= 40.
  

• Launch program TSIM by clicking Gensys -> Run Current File in the pulldown menu.

• Double-click the file mplotf/critSpeedPlot.mplotf in the mplotf-directory.

• Launch program MPLOT by pressing Ctrl+R. Select ident crit

• Estimate the critical speed in the plot. In order to make the estimate more accurate, use the middle mouse button. When the middle mouse button is pressed the position of the mouse can seen in the text fields at the top of the window.

• Calculate the critical speed defined as max.track-shift force less than 2.5[kN], by double-clicking the file ./crit.bat and press Ctrl+R.

• If the instruction above has been followed the script ./crit.bat should give the following output:

  
  Ident           Critical speed
  -----------------------------
  crit            316.200000
  
  

Make a simulation through a curve, without track irregularities.

• Copy file runf/Master.runf to runf/R600ideal.tsimf by giving the following command:
  cp runf/Master.runf runf/R600ideal.tsimf

• Open file runf/R600ideal.tsimf and change line 19 from:

  func  const    vkmh= 160        # The initial speed of the vehicle in km/h
  

  to:

  func  const    vkmh=   0        # The initial speed of the vehicle in km/h
  

  By setting vkmh= 0 the speed of the vehicle will be calculated automatically, in order to obtain a lateral acceleration of 0.65[m/s²] in the track plane (See line #240 in the input data file)



• Change lines 200-201 from:

  func const Curve_radius=  1e99                # Curve radius in [m]           
  func const Curve_cant=   0.000                # Cant of track in [m]          
  

  to:

  func const Curve_radius=   600                # Curve radius in [m]           
  func const Curve_cant=   0.150                # Cant of track in [m]          
  



• Change line 329 from:

  tstop= 10.
  

  to:

  tstop= 24.
  

• Run file runf/R600ideal.tsimf, by clicking Gensys -> Run Current File in the pulldown menu.

• Animate the results in GPLOT by writing:
  gplot runf/R600ideal.tsimf gp/R600ideal.gp &
  

• Contact forces and contact surfaces can be animated in program GPLOT.
  Select View->show_4_diags from the pulldown menu.
• Show animation in GPLOT:
  

• Animate the results in GLPLOT by writing:
  glplot runf/R600ideal.tsimf gp/R600ideal.gp &

• Show animation in GLPLOT:
  

• Display the results in MPLOT.
  Double-click the mplotf/-directory. Double-click the mplotf/Tsim_All_BoBo.mplotf-file in the right window. Select open->run with the right mouse button. In the MPLOT command line popup menu select ident R600ideal.
  In file mplotf/Tsim_All_BoBo.mplotf a number of plots are predefined, you can select plot with the radio-buttons to the right of the pulldown menu bar. The predefined plots are:
  
  • Page   #1:   Accelerations in car-body
    
  • Page   #2:   Accelerations in car-body filtered according to UIC 518
    
  • Page   #3:   Y- and Q- forces filtered according to UIC 518
    
  • Page   #4:   Track-shift forces and Y/Q-ratios filtered according to UIC 518
    
  • Page   #5:   Wear Indexes
    
  • Page   #6:   Rolling Contact Fatigue Indexes
    
  • Page   #7:   Pantograph sway and risk for vehicle turnover
    
  • Page   #8:   Car-body displacements
    
  • Page   #9:   Bogie displacements
    
  • Page #10:   Axle displacements
    
  • Page #11:   Motions and forces in secondary stops
    

Make a simulation through a curve, with track irregularities and in-line post processing.

• Copy file runf/R600ideal.tsimf to runf/R600tirr.tsimf by giving the following command:
  cp runf/R600ideal.tsimf runf/R600tirr.tsimf

• Open file runf/R600tirr.tsimf and change line 95 from:

  #  post_process= 'mplot mplotf/Tsim_All_BoBo.mplotf $IDENT'           
  

  to:

     post_process= 'mplot mplotf/Tsim_All_BoBo.mplotf $IDENT'           
  

  
  Change line 103 from:

  func char ctrack_irreg=  Ideal_track                           
  

  to:

  func char ctrack_irreg=  track_V120a                           
  

• Start the simulation, by clicking Gensys -> Run Current File in the pulldown menu.

• Inspect the results from post processor MPLOT.
  In the end of the simulation you can see that three result files were generated mplotr/R600tirr.print, diags/R600tirr.ps and mplotr/R600tirr.resu. The files have the following contents:
  
  
  • mplotr/R600tirr.print
    Output of scalars defined in command print in the file mplotf/Tsim_All_BoBo.mplotf. In current example the file has the following contents:

    car_1.m.Nmv	Mean Comfort simplified according to CEN Technical
    car_1b1.Nmv	Committee 256 WG 7 and ERRI Question B 153.
    car_1b2.Nmv	At center of car-body, over bogie #1 and over bogie #2 respectively.
    S1_max	Max lateral track-shift force
    Y/Q_1_max	Max flange climb ratio
    bt1MIN	Min vehicle turnover ratio
    car_1b2.yMAX	Max pantograph sway over trailing bogie
    car_1b2.yMIN	Min pantograph sway over trailing bogie

  • diags/R600tirr.ps
    All plots written in postscript format.
    

  • mplotr/R600tirr.resu
    Result summaries from all FTWZ- and STAT- commands given in the mplotf/Tsim_All_BoBo.mplotf-file.

  Open and inspect the results by double-clicking the files and select open->op with the right mouse button.