Mechanical APDL Basic Analysis Guide

Chapter 3: Using the Function Tool

The Function Tool allows you to define a dependent variable as a function of one or more independent
variables. Using the Function Tool, you can define complicated boundary conditions on a model, or
you can define the nonlinear material behavior for a joint element.

Example 1 Suppose that the applied displacement at a node of the model is a function of temperature
and velocity. The function is defined as follows:

u = (-0.007 * T + 0.50) Vr

where T is the temperature and Vr is the relative velocity.

The Function Tool allows you to input the function, thereby specifying the boundary condition at that
node.

Example 2 Suppose the nonlinear damping force characteristics in a joint element varies quadratically
with temperature and linearly with velocity. The function is defined as follows:

F = f(T ) Vr

or

F = (C 1 T^2 + C 2 T + C 3 ) Vr

where C 1 , C 2 , and C 3 are constants,T is the temperature, and Vr is the relative velocity.

The Function Tool allows you to input the function along with the constant values, thereby incorporating
the damping characteristics by specifying a nonlinear force that varies with relative velocity and tem-
perature.

The following Function Tool topics are available:

3.1. Function Tool Terminology

3.2. Using the Function Editor

3.3. Using the Function Loader

3.4. Applying Boundary Conditions Using the Function Tool

3.5. Function Tool Example

3.6. Graphing or Listing a Function

For more information, see Specifying a Function Describing Nonlinear Stiffness Behavior in the Material
Reference.

3.1. Function Tool Terminology

The Function Tool has two components:

• Function Editor -- Creates functions.

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