External File Format for Curve Data

  1. The file must be a text file.
  2. For Time, Temperature, and S-N Curves:
    • A row that begins with # is ignored. Use such lines for header and comment information.
    • Two numbers are then read from each row . The first number is time, temperature, or cycles depending on the curve type. The second number is a magnitude (for time and temperature curves), or stress (for S-N curves).
  3. For Load History Curves:
    Load History Curves are used to define variable amplitude fatigue events. The format described below is compatible with the SAE (Society of Automotive Engineers) standard format.
    • A row that begins with # is ignored unless it is followed by TIMEstep.
    • A row that begins with #TIMEstep specifies the sampling rate. For example #TIMEstep= 120.00 Seconds specifies that the time increment for each row is 120 seconds.
      • A TIMEstep other than zero specifies that the time column is not included. In this case, channel i refers to column i.
      • A TIMEstep of zero specifies that the first column is the time column . In this case, channel i refers to column (i+1).
      • If no row begins with #TIMEstep, channel i refers to column i (no time column).
    • When using a Load History curve from a library in a study, the program asks for the channel to be retrieved.
    • Each row can have up to 20 numbers. Usually, a comment line (beginning with #) separates data blocks.
This sample file contains a few data points of amplitude only of 1 channel only.
# This row is ignored.
#BEGIN DATA (this row is also ignored)
-999
255
-875
201
-177
433
-487
# Data continues one number in each row.
This sample file contains 3 channels (no time column).
# This row is ignored.
#TIMEstep= 0.001
-195 -296 51
-238 -318 40
-198 -307 55
-168 -297 65
# Data continues 3 numbers in each row.
This sample file contains a time column and 3 channels.
# This row is ignored.
#TIMEstep= 0 # time recorded in first column
0.00 -195 -296 51
.001 -238 -318 40
0.02 -198 -307 55
0.04 -168 -297 65
# Data continues 4 numbers in each row.