Mechanical APDL Basic Analysis Guide

Chapter 4: Initial State

The term initial state refers to the state of a structure at the start of an analysis. Typically, the assumption
is that the initial state of a structure is undeformed and unstressed; however, such ideal conditions are
not always realistic.

The initial state capability allows you to define a nontrivial state from which to start an analysis. For
example, you can specify an initial stress or strain state for a structure.

The data types supported by initial state are:

• Initial stress


• Initial strain


• Initial plastic strain


• Initial creep strain

Initial state support is also available in Distributed ANSYS.

The following topics concerning initial state are available:

4.1. Specifying and Editing Initial State Values

4.2. Initial State Application

4.3. Initial State File Format

4.4. Using Coordinate Systems with Initial State

4.5. Initial State Limitations

4.6. Example Problems Using Initial State

4.7. Writing Initial State Values

4.1. Specifying and Editing Initial State Values

The initial state capability is based on the INISTATE command. The command allows you to specify
and edit your initial state data. You can also use it to read externally supplied initial state values from
a comma-delimited file, or to export existing values in the same format.

Initial state application is element-based and available only for current-technology elements. Initial state
is applied to the elements as either an integration-point or material-based load, as follows:

• Layered elements

You can apply initial state to any combination of layer, section integration point and/or element in-

tegration points.

• Beam elements

You can apply initial state to combinations of cell number, section integration and element integration

points.

• All other elements

Applying initial state is based on the element integration point only.

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