XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> Fast Analysis (FASTAN)
A separate utility function is delivered with MSC Fatigue called FASTAN which is a program which can dramatically speed up a full analysis. This program is generally called from the MSC Fatigue forms when performing a full analysis. This is explained in
Fast Analysis, 64.
The operation of this module is as follows. The program first determines whether a single or multiple load case job is being submitted. If a single load case is being submitted, the time history file is rainflow counted and then the ensuing fatigue analysis at each location proceeds using the rainflow matrix. For a multiple load case job, the following steps are performed:
1. The original time history files are preserved for later use.
2. The original time history files are run through the peak-valley extraction program (
Peak-Valley Extraction (MPVXMUL), 227) and reduced as specified by the user using a specific gate value, number of points to retain, or a specified reduction percentage. These files are retained as
opt_xx.pvx, where xx is a 2 digit number like 01, 02, ..., 99.
3. The fatigue pre-processing (FEFAT) is performed using the reduced time histories.
4. The most damaged locations are calculated and retained in a file called jobname.ents. The number of damaged locations is specified by the user.
5. The pre-processing and fatigue analysis is performed again on only the damaged locations as specified by the user using the original time history signals.
When run in batch. Three parameters are required, and three methods are available.
Method 1 sets a specific gate value and is called as follows:
fastan /job=<jobnam> /method=1 /gate=<gate_val> /ents=<maxent>
Method 2 iterates until the modified file lengths after peak-valley slicing are reduced to a given value.
fastan /job=<jobnam> /method=2 /len=<length> /ents=<maxent>
Method 3 iterates until the peak sliced files have been reduced from the original file length by a given percentage.
fastan /job=<jobnam> /method=3 /reduct=<% reduct> /ents=<maxent>
<maxent> is optional, and specifies the maximum number of entities to be used in the abbreviated analysis.