INIPS

Bulk Data Entry Defines initial plastic strain values and settings for elements in nonlinear analysis.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS ID ETYPE CIDA
The following continuation line(s) are optional when ETYPE = SHELL. They can be used to define the sections where initial plastic strain values are applied, and they need to be given before the continuation lines starting with EORS.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
SECT NSEC SEC1 SEC2 SEC3 etc.
The following continuation lines are used to define initial plastic strain values for an element or a set of elements. They are mandatory and can be repeated as required.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
EORS EID/ESETID CIDB etc.
VALUE PS1 PS2 PS3 etc.

When ETYPE = SHELL and the SECT line is given, each VALUE line defines initial plastic strain for a shell section; and so, for any shell element (with EID) or shell element set (with ESETID), the number of VALUE lines must be NSEC.

Alternate Format (Initial Plastic Strain from H3D File)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS ID ASSIGN SUBID
EORS EID1/ESETID1 EID2/ESETID2 EID3/ESETID3 EID4/ESETID4 EID5/ESETID5 EID6/ESETID6 EID7/ESETID7
EID8/ESETID8

Example 1

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS 7
ELEM 1001
VALUE 3.33e-2 -1.67e-2 -1.67e-2 0.0 0.0 0.0
ESET 200
VALUE 3.33e-2 -1.67e-2 -1.67e-2 0.0 0.0 0.0

Example 2

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS 8 SHELL -1
SECT 2
ELEM 101
VALUE 3.33e-2 0.0 0.0
VALUE -3.33e-2 0.0 0.0
ELEM 102
VALUE 3.33e-2 0.0 0.0
VALUE -3.33e-2 0.0 0.0

Example 3 (Alternate Format - Plastic Strain from H3D File)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS 7 19 3
ELEM 1001 2002 3003

Example 4 (Alternate Format - Plastic Strain from H3D File)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
INIPS 8 29 6
ESET 2 5 9
ESET 9 19 29

Definitions

Field Contents SI Unit Example
ID Each INIPS Bulk Data Entry must have a unique ID.

No default (Integer > 0)

ETYPE Type of elements for which initial plastic strain is applied.
Blank (Default)
Applies initial plastic strain for a collection of solid and/or shell elements.
SHELL
Applies initial plastic strain for a collection of shell elements specifically.
CIDA Coordinate system identification number or flag for the plastic strain components.
Blank (Default)
The initial plastic strain components are defined in the material coordinate system for solids and in element coordinate system for shells.
-2
Components are defined in the material coordinate system.
-1
Components are defined in the element coordinate system.
0
Components are defined in the basic coordinate system.
Integer > 0
Components are defined in a user-defined (prescribed) coordinate system.
SECT Keyword indicating the start of continuation line(s) for the shell sections.
NSEC Number of shell sections where initial plastic strain is applied for shell elements.

No default (1 ≤ Integer ≤ 6)

SEC(i) Through-thickness position for the shell sections. SEC(i) must be either all blank or all non-blank, that is, the number of SEC(i) must be either NSEC or zero; and SEC(i) must be given in ascending order if all non-blank.

If left blank, this implies the sections are located uniformly through the shell thickness, starting at the bottom surface and ending at the top surface.

A Real value is the multiplier to shell thickness to find the location. -0.5 is the bottom surface of the shell element and 0.5 is the top surface.

The through-thickness positive direction, pointing from the bottom surface to the top surface, is determined by the right-hand rule and the order in which the grid points are listed on the connection entry. It is the same as the convention for Z1/Z2 of PSHELL.

Default = Blank (Blank or -0.5 ≤ Real ≤ 0.5)

EORS Flag indicating an element, or an element SET is selected in the following field.
ELEM (Default)
Element is selected.
ESET
Element SET is selected.
EID/ESETID Identification number of the element or the element SET to which the plastic strain values apply.

No default (Integer > 0)

CIDB Coordinate system identification number or flag for the plastic strain components.
Blank (Default)
This implies CIDA is used. All other options suppress CIDA.
-2
Initial plastic strain components are defined in the material coordinate system.
-1
Components are defined in the element coordinate system.
0
Components are defined in the basic coordinate system.
Integer > 0
Components are defined in a user-defined (prescribed) coordinate system.
VALUE Keyword indicating the start of a continuation line for the plastic strain components.
PS(i) Plastic strain components. 4

No default (Real)

Alternate Format Description (plastic strain from H3D file)
ASSIGN Identification number of ASSIGN, H3DRES. When ASSIGN is specified, SUBID should also be specified and the VALUE continuation line is not allowed.

This field is mandatory for Alternate Format (plastic strain from H3D file).

No default (Integer > 0)

SUBID Subcase identification number where initial plastic strain is applied from the H3D file.

This field is mandatory for Alternate Format (plastic strain from H3D file).

No default (Integer > 0)

EORS Flag indicating an element, or an element SET is selected in the following field.
ELEM (Default)
Element is selected.
ESET
Element SET is selected.
EID#/ESETID# Identification number of the element or the element SET to which the plastic strain values apply.

No default (Integer > 0)

Comments

  1. INIPS and IPSADD should not have the same ID.
  2. The INIPS Bulk Data Entry is selected by the Subcase Information Entry INIPS.
  3. Initial plastic strain is only supported for nonlinear static analysis (both small and large displacement analysis). Initial plastic strain is supported for solid elements (CHEXA, CPENTA, CPYRA and CTETRA) and shell elements (CQUAD4, CTRIA3, CQUAD8 and CTRIA6), only.
    Initial plastic strain is currently not supported for:
    • Solid elements with user-defined material in LGDISP analysis.
    • Elements with MATMDS material.
  4. For initial plastic strain of solid elements, the following 6 plastic strain components are needed for each VALUE:
    • PS1 - ε xx p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae ymaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeiEaiaabIha aeaacaqGWbaaaaaa@3F09@
    • PS2 - ε yy p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae OmaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeyEaiaabMha aeaacaqGWbaaaaaa@3F0C@
    • PS3 - ε zz p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae 4maiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeOEaiaabQha aeaacaqGWbaaaaaa@3F0F@
    • PS4 - ε xy p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae inaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeiEaiaabMha aeaacaqGWbaaaaaa@3F0D@
    • PS5 - ε yz p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae ynaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeyEaiaabQha aeaacaqGWbaaaaaa@3F10@
    • PS6 - ε zx p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae OnaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeOEaiaabIha aeaacaqGWbaaaaaa@3F10@

    Where x, y, and z are the axes of the coordinate system selected via CIDA and CIDB.

    For initial plastic strain in element or material coordinate system of shell elements, the following 3 plastic strain components are needed for each VALUE line:
    • PS1 - ε 11 p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae ymaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaGymaiaaigda aeaacaqGWbaaaaaa@3E89@
    • PS2 - ε 22 p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae OmaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaGOmaiaaikda aeaacaqGWbaaaaaa@3E8C@
    • PS3 - ε 12 p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae 4maiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaGymaiaaikda aeaacaqGWbaaaaaa@3E8C@
    Where 1 and 2 are the first two local directions in the element or material coordinate system.
    For initial plastic strain in the basic or a prescribed coordinate system of shell elements, the following 6 plastic strain components are needed for each VALUE line:
    • PS1 - ε xx p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae ymaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeiEaiaabIha aeaacaqGWbaaaaaa@3F09@
    • PS2 - ε yy p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae OmaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeyEaiaabMha aeaacaqGWbaaaaaa@3F0C@
    • PS3 - ε zz p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae 4maiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeOEaiaabQha aeaacaqGWbaaaaaa@3F0F@
    • PS4 - ε xy p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae inaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeiEaiaabMha aeaacaqGWbaaaaaa@3F0D@
    • PS5 - ε yz p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae ynaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeyEaiaabQha aeaacaqGWbaaaaaa@3F10@
    • PS6 - ε zx p MathType@MTEF@5@5@+= feaahqart1ev3aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbwvMCKfMBHbqee0evGueE0jxy aibaieYlf9irVeeu0dXdh9vqqj=hEeeu0xXdbba9frFj0=OqFfea0d Xdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXdbPYxe9vr0=vr0=vq pWqaaeaabiGaciaacaqabeaabiWacqaaaOqaaiaabcfacaqGtbGaae OnaiaaykW7caqGTaGaaGPaVlaabw7adaqhaaWcbaGaaeOEaiaabIha aeaacaqGWbaaaaaa@3F10@
    Where, x, y, and z are the axes of the basic or prescribed coordinate system.
  5. Alternate Format (Plastic strain from H3D file):
    1. VALUE continuation line is not allowed for the Alternate Format when plastic strain is sourced from the H3D file.
    2. For shell elements, currently only the equivalent of NSEC=2 is supported (Z1 and Z2 layers) to apply the plastic strain, as the number of layers where plastic strain data is available can be identified from the H3D file.
    3. Currently, only H3D files output from OptiStruct and HyperForm are supported.