Mechanical APDL Basic Analysis Guide

For coupled-field elements CPT212,CPT213,CPT215,CPT216, and CPT217, the initial stresses to be applied
are Biot’s effective stress. They are automatically written out when the output stress option is specified
(INISTATE, WRITE, , , , , ,S).

The following example listing shows how initial stress can be applied in such cases:

Constant Initial Stress on the Whole Model

inistate,defi,,,,,100,200,300,400,500,600

Apply Constant Stress of SX=100 On Beam Element 1

inistate,defi,1,,,,100

Apply a Stress of SX=33.333 at Elem Integration Pt 3 within Element 2

inistate,defi,2,3,,,33.3333

Apply Constant Stress Of SX=200 in Cell 2 For All Selected Beam Elements

inistate,defi,,,2,,200

Apply Constant Stress Of SX=200 For All Beams In A Model

And Wherever There Is Material=3

inistate,set,mat,3

inistate,defi,,,,,200

Apply a Stress of SX=100,SY=200,SXY=150 for Layers 1,3,5 and

SX=200,SY=0 for Layers 2,4,6 in a Layered Shell Element. Layer

1,3,5 have material 1 and Layer 2,4,6 have material 2.

inistate,defi,,,1,,100,200,150

inistate,defi,,,2,,200

inistate,defi,,,3,,100,200,150

inistate,defi,,,4,,200

inistate,defi,,,5,,100,200,150

inistate,defi,,,6,,200

OR

inistate,set,mat,1

inistate,defi,,,,,100,200,150

inistate,set,mat,2

inistate,defi,,,,,200

Apply a Stress of SX=33.333 at Reinf 1 for all elements

inistate,defi,,,1,,33.3333

For initial stress example problems, see Example: Initial Stress Problem Using the IST File (p. 99) and
Example: Initial Stress Problem Using the INISTATE Command (p. 100).

4.2.2. Initial Strain Application

The initial stress application example can be ext ended for initial strain by simply changing the data
type to EPEL, as shown:

! Constant Initial Strain on the Whole Model

inistate,set,dtyp,epel

inistate,defi,,,,,0.1,-0.01,-0.01

!Apply a Constant Strain of EPEL X=0.01 On Beam Element 1

inistate,set,dtyp,epel

inistate,defi,1,,,,0.01

!Apply a Strain of EPEL X=0.01 at Elem Integration Pt 3 within Element 2

inistate,set,dtyp,epel

inistate,defi,2,3,,,0.01

!Apply a Constant Strain Of EPEL X = 1E-6 in Cell 2 For All Selected Beam Elements

inistate,set,dtyp,epel

inistate,defi,,,2,,1E-6

!Apply a Constant Strain Of EPEL X=1E-3 For All Beams In A Model

!And Wherever There Is Material=3

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Initial State Application