Calculation of wheel unloading on twisted track

Program QUASI in the GENSYS package can be used when calculating wheel unloading on twisted track. In order to make the calculation of wheel unloading the input data file has to be prepared in the following way.

Use a cylindrical wheel profile, to avoid unwanted roll angle between trc and axl. Example:

                                               
  insert file  $genkpf/kpf_ckona_fl.kpfr       
  in_substruct kpf_ckona [ " " 0. 0. 0. ]

Rotate the trc-masses in roll direction by func-commands, in order to create the twisted track. Example:

                                
  func copy trc_111.f= 0.037    
  func copy trc_112.f= 0.017    
  func copy trc_121.f= -.017    
  func copy trc_122.f= -.037

Set lateral constraints to the wheelsets. Since the wheels don't have a conicity, lateral constraints has to be applied to avoid a yawing motion of the vehicle. Example:

                                        
  constr fix_rigid_1 axl_111 y 0.000    
  constr fix_rigid_1 axl_112 y 0.000    
  constr fix_rigid_1 axl_121 y 0.000    
  constr fix_rigid_1 axl_122 y 0.000

Set friction coefficient between wheel and rail equal to 0.(zero), in order to avoid the lateral creep forces to affect the wheel unloading.

                           
  func const mu= 0.0

Save vertical wheel-rail forces by command "s_var scalar_0". Can also be done by using the substructures save_axl1.ins, scal_axl1.ins or save.bobo.scal. Example:

                                                    
  s_var scalar_0 knwr.F0_     # Nominal wheel load  
                                                    
  s_var scalar_0 Q111r   s_var scalar_0 Q111l       
  s_var scalar_0 Q112r   s_var scalar_0 Q112l       
  s_var scalar_0 Q121r   s_var scalar_0 Q121l       
  s_var scalar_0 Q122r   s_var scalar_0 Q122l

Perform a quasi static analysis in program QUASI.

Post-process the vertical wheel-rail forces in MPLOT by following input data

##                                                                
##                                                                
##      Input data file for program MPLOT                         
##                                                                
##      calculating of wheel unloading                            
##                                                                
##                                                                
 func operp unload111r= ( Q111r - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload111l= ( Q111l - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload112r= ( Q112r - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload112l= ( Q112l - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload121r= ( Q121r - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload121l= ( Q121l - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload122r= ( Q122r - knwr.F0_ ) / knwr.F0_ - 1.      
 func operp unload122l= ( Q122l - knwr.F0_ ) / knwr.F0_ - 1.      
                                                                  
                                                                  
 print scalar Q111r Q111l                                         
              Q112r Q112l                                         
              Q121r Q121l                                         
              Q122r Q122l                                         
                                                                  
 print scalar unload111r unload111l                               
              unload112r unload112l                               
              unload121r unload121l                               
              unload122r unload122l                               
                                                                  
 stop