Mechanical APDL Basic Analysis Guide

Each line of the initial stress file has 10 columns, as follows:

• The element ID Number


• The element integration point (for standard elements)


• The layer (for layered elements) or the cell number (for beams)


• The section integration point (for beams and shells only)


• The six stress/strain components

Any of the parameters for element ID, element integration point, layer number, cell number, or section
integration point can be set to ALL. For example,

1,all,all,all, 100, 0, 0, 0, 0, 0

applies an equal stress of SX = 100 to all integration points or layers of the element ID = 1.

This input line

all,all,all,all, 100, 0, 0, 0, 0, 0

applies an equal stress of SX = 100 to all integration points or layers to all of the selected elements.

You can provide additional parameters via the /ATTR,VALUE line in the .IST file. Supported parameters
are CSYS and DTYP. Issue a CSYS,VALUE command to specify the coordinate system to be used for the
subsequent data supplied in your .IST file. The default coordinate system is the global Cartesian system.

You can apply initial strain in a similar manner by including /DTYP,EPEL before the actual initial-
state/initial-strain date. For example,

/dtyp,epel

all,all,all,all, 0.1, 0, 0, 0, 0, 0

applies an initial strain of ex = 0.1 for all elements in the database.

You can insert comments and other non-analysis information in the .IST file by preceding them with
an exclamation mark (!).

4.4. Using Coordinate Systems with Initial State

The INISTATE command provides options for specifying data in coordinate systems other than the
material and element coordinate systems. To define the coordinate system, issue this command:

INISTATE,SET,CSYS,CSID

Valid values for CSID are MAT (material) or ELEM (element), or any user-created coordinate system.

Shell elements support only material and element coordinate systems. Link elements support only element
coordinate systems.

The default coordinate systems are 0 (global Cartesian) for solid elements, and ELEM for shell, beam
and link elements.

4.5. Initial State Limitations

The following initial state element limitations apply:

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

Initial State