Custom Unit Sets

Define a custom set of units for the material properties to be used with the finite element model.

In accordance with the Define a Helius PFA Composite Material section, you can set user material constant #1 to a value of 5 and add the following keyword and data line to the HIN file. 
*CUSTOM UNITS
Fconv, Lconv, Tconv, tconv

As an example of a custom system of units, let's say that a finite element model is created using units of kilonewtons, centimeters, degrees Fahrenheit, and seconds. Since this particular system of units is not one of the four standard systems of units, it will be considered a custom system of units. Consequently the 1st user material constant for any Helius PFA materials should be assigned a value of 5. Now we must compute the conversion factors for force, length, temperature, and time that will be listed in the corresponding HIN file. The force conversion factor required to convert from the default units of Newtons to the desired units of kilonewtons is computed as,

The length conversion factor required to convert from the default units of meters, to the desired units of centimeters is computed as,

The conversion factor for temperature changes (ΔT) required to convert from the default units of K to the desired units of °F is computed as,

Finally, the conversion factor for time from seconds will be 1.0. Not all Abaqus/Standard and Explicit analyses require a time conversion. Therefore, it is suggested you always specify this value as 1.0.

The corresponding entry in the HIN file to the custom set of units described will be expressed as shown below. 
*CUSTOM UNITS
0.001, 100, 1.8, 1.0
In this case, the data line immediately following the *USER MATERIAL statement in the Abaqus input file would appear as shown below. The first user material constant (value=5) indicates that a 'custom' system of units will be used. 
*USER MATERIAL, CONSTANTS=16
5, 1, 1, 0, 0, 0, 0, 0, 
0, 0, 0, 0.1, 0.01, 0, 0, 0

Two additional points should be emphasized regarding the choice of values for the 1st user material constant. First, all stress results printed in the Abaqus output files will be expressed in the units you specified via the first user material constant. For example, if the first user material constant has a value of 3 (specifying the pound, inch, degree Rankine system of units), Abaqus will output all stresses in units of lb/in2. Second, custom units are not supported by the Helius PFA GUI.

Parent topic: The HIN File