You can create an equation constraint by entering data in the Edit Constraint dialog box. The terms of an equation consist of a coefficient applied to a degree of freedom of every node in a set. For detailed information about equations, see “Linear constraint equations,” Section 35.2.1 of the Abaqus Analysis User's Guide.
To create an equation constraint:
From the main menu bar, select Constraint
Create.
Tip:
You can also create an equation constraint using the 
tool in the Interaction module toolbox.
In the Create Constraint dialog box that appears, do the following:
Name the constraint. For more information about naming objects, see “Using basic dialog box components,” Section 3.2.1.
From the Type list, select Equation, and then click Continue.
The constraint editor appears.
In the table in the editor, enter a row of data for each term in the equation. The equation must have at least two terms. Click 
for a description of the relationship between the data in the table and the desired equation.
Each row should contain the following information:
The coefficient.
The name of an existing set. (For information on creating sets, see Chapter 73, “The Set and Surface toolsets.”) You can enter a set that contains one or more points in the first row of the table. Subsequent sets must contain only a single point.
The degree of freedom.
The ID of the coordinate system in which you will apply the constraint. You can either accept the default coordinate system or select an existing datum coordinate system. If the desired datum coordinate system does not exist, you can create it using the Datum toolset. (For more information, see “Creating datum coordinate systems,” Section 62.9.)
To determine the ID of a coordinate system, select ToolsQuery from the main menu bar. For more information, see “Obtaining general information about the model,” Section 71.2.2.
Click OK to save your equation definition and to close the constraint editor.
