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Users Manual for Program TRC_PSDPL  





Table of Contents

   Introduction
   Calculation procedure
   Input data commands
   Output data
   Example



Introduction

Program TRC_PSDPL plots the PSD spectra of a track.



Calculation procedure

Read the input data file and if the distance between two consecutive points in longitudinal direction are bigger than 0.5 [m], program TRC_PSDPL will spline interpolate more points in file INFIL. The PSD-spectra is obtained by calculating the Fourier-spectra of the autocorrelation spectra of the signal. After the PSD-spectra has been calculated it will pass a Hanning window, in order to make it smoother.



Input data commands

Input data is read in free format, valid separators between the input values are <space>, <comma>, <tab>, <equal sign> or <carriage return>. The commands can be written both in lower and upper case letters. The operation of the program is controlled by the commands described below; some of the commands also need arguments.


BO
Lateral semi spacing between contact points.
Declared= Real*8    Default= 0.75

DRAW_ERRI_LEVELS
Draw high and low levels according to ERRI B 176/DT 290 in the diagrams.
Declared= Character*3    Default= 'yes'

IDENT
Ident line which will be written in the plots.
Declared= Character*80    Default= Blank

INFIL
Input track data file
The file is read in free format. The columns in the file shall have the same contents as in a trac-, trax- or trax_wdesign- file.
Declared= Character*132    Default= Blank

LXCM
Length of the X-axle.
Declared= Real*8    Default= 4 [cm]

LYCM
Length of the Y-axle.
Declared= Real*8    Default= 12 [cm]

PAPER_FORMAT
Select paper format to plot on.
A4P= A4 Portrait
A4L= A4 Landscape
A3P= A3 Portrait
etc.
Declared= Character*3    Default= 'A4P'

POSTFI
Printer file.
Declared= Character*80    Default= 'trc_psdpl.ps'

PRINT_PSD
Print the PSD-spectras on external files.
Declared= Character*3    Default= 'yes'

PSD_METHOD
Type of method to be used when calculating the PSD-spectra.
PSD_METHOD can be set equal to FOUR or CORR. If method FOUR is used the PSD-spectra will be calculated via the Fourier spectra. If method CORR is used the PSD-spectra will be calculated via the auto-correlation spectra.
Declared= Character*4    Default= 'FOUR'

PSDPLR_DIR
Directory to write the resulting spectras in.
In addition to the plots, the spectras are also written to files, for later post-processing in OCTAVE or MATLAB. These output spectras are stored in directory PSDPLR_DIR.
Declared= Character*132    Default= 'psdplr'

SMOOTH_LOW
Smoothing of the PSD-spectra in the low frequency region.
A higher value will give a smoother spectra.
Declared= Real*8    Default= 28.

SMOOTH_HIGH
Smoothing of the PSD-spectra in the high frequency region.
A higher value will give a smoother spectra.
Declared= Real*8    Default= 36.

XMOVE
Length for shifting the track when calculating the autocorrelation. The bigger XMOVE the better accuracy. XMOVE can not be bigger than the double length of XSTOP - XSTART.
N.B. Variable XMOVE is only used if PSD_METHOD equals CORR.
Declared= Real*8    Default= 300 [m]

XRAMP
Cosinus shaped ramps applied in the beginning and in the end of the curves. In order to eliminate disturbances from the ends of the curves.
Declared= Real*8    Default= 100 [m]

XSTART
Longitudinal coordinate from where file INFIL will be read.
Declared= Real*8    Default= 0. [m]

XSTOP
Longitudinal coordinate where reading of file INFIL will end.
Declared= Real*8    Default= 1.E20 [m]

XCMPDEC
Plotting scale factor.
Declared= Real*8    Default= 2.[cm/decade]

X_LEFT
Left end of the X-axis.
Declared= Real*8    Default= 1e-2 [(1/m)]

YCMPDEC
Plotting scale factor.
Declared= Real*8    Default= 2.[cm/decade]

Y_BOT
The value of the Y-axis at bottom.
Declared= Real*8    Default= 1e-2 [mm2/(1/m)]


Output data

The output data consists of m-files and diagrams:

m-files written in directory PSDPLR_DIR are:
PSD_GAUGE.m = PSD-spectra of the gauge irregularities [mm2/(1/m)]
PSD_FI.m = PSD-spectra of the superelevation irregularities [rad2/(1/m)]
PSD_LAT.m = PSD-spectra of the lateral Y-mid irregularities [mm2/(1/m)]
PSD_VERT.m = PSD-spectra of the vertical Z-mid irregularities [mm2/(1/m)]
vPSD_GAUGE.m = PSD-spectra of the derivatives of the gauge irregularities [mm2]
vPSD_FI.m = PSD-spectra of the derivatives of the superelevation irregularities [rad2]
vPSD_LAT.m = PSD-spectra of the derivatives of the lateral Y-mid irregularities [mm2]
vPSD_VERT.m = PSD-spectra of the derivatives of the vertical Z-mid irregularities [mm2]
aPSD_GAUGE.m = PSD-spectra of the second derivatives of the gauge irregularities [mm2/m]
aPSD_FI.m = PSD-spectra of the second derivatives of the superelevation irregularities [rad2/m]
aPSD_LAT.m = PSD-spectra of the second derivatives of the lateral Y-mid irregularities [mm2/m]
aPSD_VERT.m = PSD-spectra of the second derivatives of the vertical Z-mid irregularities [mm2/m]


Diagram #1 shows:   LAT = Lateral Y-mid irregularities [mm2/(1/m)]
  VERT = Vertical Z-mid irregularities [mm2/(1/m)]
  GAUGE = Gauge irregularities [mm2/(1/m)]
  CANT = Cant irregularities [mm2/(1/m)]




Diagram #2 shows:   vLAT = First derivative of Lateral Y-mid irregularities [mm2]
  vVERT = First derivative of Vertical Z-mid irregularities [mm2]
  vGAUGE = First derivative of Gauge irregularities [mm2]
  vCANT = First derivative of Cant irregularities [mm2]




Diagram #3 shows:   aLAT = Second derivative of Lateral Y-mid irregularities [mm2/m]
  aVERT = Second derivative of Vertical Z-mid irregularities [mm2/m]
  aGAUGE = Second derivative of Gauge irregularities [mm2/m]
  aCANT = Second derivative of Cant irregularities [mm2/m]


The units in the diagrams above depends on the units used in INFIL. In track formats trac, trax or trax_wdesign the units of the irregularities are in [mm].




Example of an input data file

Following example: Master.trc_psdplf can be used as a master file:

##
##    Input data file for program TRC_PSDPL
##

  PSD_METHOD= FOUR   XRAMP= 100
  PRINT_PSD = yes

  IDENT= 'track/Cst-G_293-294.trax_wdesign'
  INFIL=  track/Cst-G_293-294.trax_wdesign

  XSTART= 0       XSTOP= 1.e20


##
## Plotting data
## ----------------
  PAPER_FORMAT= a3p
  LXCM= 10         LYCM= 18
  X_LEFT= 1e-2     XCMPDEC= 4
  Y_BOT = 1e-6     YCMPDEC= 2

  SMOOTH_LOW = 28  SMOOTH_HIGH= 36

  ILASER= 9        POSTFI= diags/trc_psdpl.pdf