Mohammad Nasseri To utilize multiple field variables in Abaqus using the usdfld/vusdfld subroutine, you need to define the field variables in the material manager and in the subroutine code appropriately. Here are the steps to follow:

In the material manager, define the field variables using the "Field Variable" section. To define multiple field variables, click on the "Add" button to add a new field variable. Then, define the name, type, and units of the field variable.

In the subroutine code, you can access the field variables using the "sdv" array. The "sdv" array is an array of all the state-dependent variables defined in the material. The state-dependent variables include the field variables and any other state variables that are defined in the material.

To separate the two field variables in the subroutine code, you need to use the correct indices of the "sdv" array. The first field variable will have an index of 1, the second field variable will have an index of 2, and so on.

For example, if you have two field variables named "TEMP" and "STRAIN" defined in the material manager, you can access them in the subroutine code as follows: