MATF

Format

Example

Definitions

Comments

1. MID field may refer to MAT1, MAT2, MAT8, MAT9 or MAT9OR entries.
2. For laminated shells (PCOMP/PCOMPP/PCOMPG).
   V1, V2, through V5 specify material stress/strain limits.

   V1

   Tensile stress/strain limit in longitudinal direction

   V2

   Compressive stress/strain limit in longitudinal direction

   V3

   Tensile stress/strain limit in lateral direction

   V4

   Compressive stress/strain limit in lateral direction

   V5

   In-plane shear stress/strain limit

   For STRS failure criterion, the input allowables should be stress-allowables.

   For STRN failure criterion, the input allowables should be strain-allowables. OptiStruct will not conduct internal conversion for STRN failure criterion. The values defined are directly used as strain-allowables for STRN failure criterion on MATF.

   For STRN failure criterion, the STRN field on MAT8 entry has no effect on the allowable values defined on the MATF entry.

   For Solid Elements (MAT9/MAT9OR) and Continuum Shells (PCOMPLS).

   V1, V2 through V9 specify material stress/strain limits.

   V1

   Tensile stress/strain limit in 1-1 direction

   V2

   Compressive stress/strain limit in 1-1 direction

   V3

   Tensile stress/strain limit in 2-2 direction

   V4

   Compressive stress/strain limit in 2-2 direction

   V5

   Tensile stress/strain limit in 3-3 direction

   V6

   Compressive stress/strain limit in 3-3 direction

   V7

   Shear stress/strain limit in 1-2 direction

   V8

   Shear stress/strain limit in 2-3 direction

   V9

   Shear stress/strain limit in 1-3 direction

   Coordinate system 1-2-3 are user-defined for continuum shell elements or solid elements with MAT9.

   For STRS3D failure criterion, the input allowables should be stress-allowables.

   For STRN3D failure criterion, the input allowables should be strain-allowables. OptiStruct will not conduct internal conversion for STRN3D failure criterion. The values defined are directly used as strain-allowables for STRN3D failure criterion on MATF.

3. V10, V11, and V12 are used for TSAI/TSAI3D criterion.
   • For TSAI:
     • V10: the coupling coefficient $C_{12}$ for the ${\sigma }_1{\sigma }_2$ term.
     • If V10 is blank, the coupling coefficient is calculated from W1.
     • If V10 and W1 are both blank, the coupling coefficient is 0.0.
   • For TSAI3D:
     • V10: the coupling coefficient $C_{12}$ for the ${\sigma }_1{\sigma }_2$ term.
     • V11: the coupling coefficient $C_{23}$ for the ${\sigma }_2{\sigma }_3$ term.
     • V12: the coupling coefficient $C_{12}$ for the ${\sigma }_1{\sigma }_3$ term.
     • If V10, V11, and V12 are all blank, the coupling coefficients are calculated from W1, W2, and W3.
     • If V10, V11, and V12 and W1, W2, and W3 are all blank, the coupling coefficients are 0.0.
4. W1, W2, W3, and W4 definition is dependent on the failure criterion specified.
   • PUCK/PUCK3D specify failure envelope parameters:

     W1

     Failure envelope factor 12(-)

     W2

     Failure envelope factor 12(+)

     If W2 is blank, it is set to be equal to W1, W1 and W3 should be specified.

     W3

     Failure envelope factor 22(-)

     W4

     Failure envelope factor 22(+).

     This is only used for PUCK3D.

   • TSAI3D on anisotropic solid material

     If V10, V11 and V12 are blank, they are the tensile stress limits in equal-biaxial tension tests. W1 is the tensile stress limit in equal-biaxial tests where the two tensile loads are in directions 1 and 2. W1 is mandatory, while W2 and W3 are optional. If W2 and W3 are not specified, then they are set equal to W1. The definition of W2 and W3 is similar to W1. W2 is the tensile stress limit in equal-biaxial tension tests where the two tensile loads are in directions 2 and 3. W3 is the tensile stress limit in equal-biaxial tension tests where the two tensile loads are in directions 1 and 3.

     If V10, V11 and V12 are defined, W1, W2 and W3 are ignored for TSAI3D.

   • HASH3D

     When Hashin failure criteria is applied on continuum shell elements, W1 is defined as alpha, which takes the transverse shear stress (in 1-2 and 1-3 direction) into account in the tensile fiber check. When W1 is blank, alpha is assumed to be 1.0.

   • CNTZ3D
     When using Cuntze failure criterion, W1 and W2, corresponding to the two free curve parameters, $b_{\perp \left|\right|}$ and $b_{\perp }^T$ should be provided. The two curve parameters can be determined from multi-axial test data from experiments. Bounds on the safe side for GFRP, CFRP and AFRP are assumed by Cuntze ¹ to be:(1)

     $$\mathrm{0.0.5}<b_{\perp \left|\right|}<0.15,1.0<b_{\perp |}^T<1.6$$
5. When some failure criteria are defined on both PCOMP(G/P) (allowables on MATi) and MATF, then:
   • If the same criterion type is defined in both PCOMP(G/P) property and the MATF entry, then the allowables defined on the MATF entry will be used in the failure criterion calculations. The MATF entry overwrites the allowables defined by the corresponding MATi entry (if any).
   • If some criteria are only defined on PCOMP(G/P) but not on MATF, then for such criteria, the allowables are taken from corresponding MATi entries.
   • If some criteria are defined on MATF, and PARAM,ALLFT,YES exists, then the criteria defined on MATF will use the allowables defined on MATF. However, the criteria not defined on MATF will be calculated based on allowables defined on the corresponding MATi entry.
6. The following criteria can only be defined on the MATF entry.

   PUCK, DUCTILE, PUCK3D, HILL3D, HOFF3D, TSAI3D, HASH3D, STRN3D, and CNTZ3D.

   The rest of the criteria can also be defined on the FT field of the corresponding PCOMPP/PCOMPG/PCOMP entry.

   For the PUCK failure criterion, even though it is available on the FT field of the PCOMPP/PCOMPG/PCOMP entry, the corresponding failure envelope factors (W1, W2, W3) can only be defined on the MATF entry. Therefore, the MATF entry is mandatory when PUCK failure criterion is requested via the FT field of PCOMP/PCOMPG/PCOMPP entries, and additionally, the allowables should be defined on the MATF for PUCK criterion only. To use PUCK failure criteria, the MATF entry should be specified with MID referring to the corresponding material entry.

7. If the CRITERIA field is set to DUCTILE, then the TID field should point to a TABLEMD entry with NDEP set to 1. The first data column (Yi) is the equivalent plastic strain at the onset of damage. The second data column (Xi) is the corresponding temperature. The second column should be specified in ascending order only.

   When the CRITERIA field is set to DUCTILE in OSTTS analysis, the temperature-based lookup is conducted for each temperature to identify the corresponding equivalent plastic strain from the TABLEMD entry. This plastic strain is used in conjunction with the calculated von Mises Strain to calculate Damage (This can be output using the DAMAGE I/O Options Entry).

8. The following tables summarize the supported failure criteria with different properties and materials.

   Table 1. Shell Elements

   	PSHELL	PCOMP/PCOMPG/PCOMPP
   	MAT1/MAT2/MAT8
   HILL	No	Yes
   HOFF	No	Yes
   TSAI	No	Yes
   STRN	No	Yes
   STRS	No	Yes
   HASHIN	No	Yes
   PUCK	No	Yes
   DUCTILE	No	Yes

   Table 2. Solid Elements

   	PSOLID		PCOMPLS
   	MAT9	MAT9OR	MAT9	MAT9OR
   HILL3D	Yes	Yes	Yes	Yes
   HOFF3D	Yes	Yes	Yes	Yes
   TSAI3D	Yes	Yes	Yes	Yes
   STRN3D	Yes	Yes	Yes	Yes
   STRS3D	Yes	Yes	Yes	Yes
   HASH3D	No	Yes	Yes	Yes
   PUCH3D	No	Yes	Yes	Yes
   CNTZ3D	No	Yes	Yes	Yes

9. Multiple different failure criteria can be defined on a single MATF entry. Therefore, the CRI continuation line can be repeated, and multiple different failure criteria can be specified. However, a particular failure criterion can only appear once on the MATF entry and cannot be repeated. Different failure criteria for different materials can be defined by referencing the corresponding material entry (with same ID as MATF) on MID# fields of the PCOMP(G) and PLY entries (for PCOMPP). If different failure criteria are required to be defined for a single composite property, then MATF entry should be used.