# Fatigue Configuration File

The fatigue configuration file is a user-defined external ASCII-file through which the data groups from results of static/modal/transient analysis of different solvers can be read.

This data is available for fatigue analysis. Previous HyperMesh versions (4.0 and below) supported only results of Nastran and Abaqus solvers. HyperMesh 5.0 and after allows you to use the results of different solvers to generate data for fatigue analysis.

A fatigue configuration file should be named Fatigue.cfg. This file is sourced into HyperMesh when HyperMesh is first invoked. HyperMesh looks for the first file it finds in the following locations and order:
1. The local working directory.
2. Your home directory (looks at the "HOME" environment variable).
3. The HyperMesh bin directory.

Each file should consist of one or more data groups. Each group is defined by a group name (denoted by having an ‘*’ leading the group name line), followed by 1-12 data type lines.

You can comment out any line in the fatigue.cfg file by having either a ‘#’,’\$’, or ‘/’ lead the line.

An example of a valid data group is shown below.
*My Unique Group
SX = Normal Stress X (solids)
SZ = Normal Stress Z (solids)
#SXY = Shear Stress XY (solids)
SYZ = Shear Stress YZ (solids)
SXZ = Shear Stress XZ (solids)

Notice that SY is not defined, and that SXY is commented out. HyperMesh assumes that each missing data type value is 0. In this case, both SY and SXY are considered missing.

Note: A data group name (My Unique Group, in this case) can be any string the group creator wants it to be.

You do not need to set SX = Normal Stress X (Solids)If the solver you are using calls for SX to be set to whatever SZ is, you can simply set SX = Normal Stress Z (Solids)

Note: Any line that HyperMesh does not recognize is ignored. If you use an invalid data type (such as SSX instead of SX), HyperMesh will set SX equal to 0. See the next section for valid data types.

## Valid Data Types

The first character in the data type identifier string determines if the group is a Stress (S), Force (F), Moment (M), or Strain (E) group. The S in SX refers to a stress group.

For normal stress and strain groups HyperMesh allows the following strings:
Stresses = SX, SY, SZ, SXY, SYZ, SXZ
Strains = EX, EY, EZ, EXY, EYZ, EXZ
For top-and-bottom stress and strain groups HyperMesh allows the following strings:
Stresses = SX1, SY1, SZ1, SXY1, SYZ1, SXZ1, SX2, SY2, SZ2, SXY2, SYZ2, SXZ2
Strains = EX1, EY1, EZ1, EXY1, EYZ1, EXZ1, EX2, EY2, EZ2, EXY2, EYZ2, EXZ2
For force and moment groups HyperMesh allows the following string:
F & M = FX1, FY1, FZ1, MX1, MY1, MZ1, FX2, FY2, FZ2, MX2, MY2, MZ2 

Depending on which type of group you are defining, HyperMesh assumes that any undefined data type identifiers (which are allowed) to be 0. If you provide an improper data type identifier (one not on any of the above lists), the line is ignored.

## Negation

There is a method to negate the value of a data type. For example, if the data type Normal Stress X (solids) is found to be 0.2 for a given element, it means that SX is set to 0.2 with the following line:
SX = Normal Stress X (solids)(SX = 0.2)
You can negate the unit by using either of the following methods:
SX = -Normal Stress X (solids)
Or
SX = Normal Stress X (solids); -1.0 (SX = -0.2 in either case)