MATF

Bulk Data Entry Defines material properties and failure model parameters for Failure criteria calculations.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
MATF	`MID`
	`CRI`	`CRITERIA`	`TID`/`V1`	`V2`	`V3`	`V4`	`V5`	`V6`
	`V7`	`V8`	`V9`					`W1`
	`W2`	`W3`
	etc

Example

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
MATF	100
	CRI	PUCK	3.E5	3.E5	3.E5	3.E5	3.E5
								0.25
	0.25	0.25

Definitions

Field	Contents	SI Unit Example
`MID`	Material identification number. (Integer > 0)
`CRI`	`CRI` flag indicating that the failure criterion input data are to follow. 8
`CRITERIA`	Character String representing the chosen failure criterion. PUCK Puck failure criterion. HILL Hill failure criterion. HOFF Hoffman failure criterion. TSAI Tsai-Wu failure criterion. HASH Hashin failure criterion. STRN Maximum strain failure criterion. DUCTILE Damage initiation criterion. PUCK3D Puck failure criterion for continuum shell elements. HILL3D Hill failure criterion for continuum shell elements/solid elements with anisotropic material. HOFF3D Hoffman failure criterion for continuum shell elements/solid elements with anisotropic material. TSAI3D Tsai-Wu Failure criterion for continuum shell elements/solid elements with anisotropic material. HASH3D Hashin failure criterion for continuum shell elements. STRND3D Maximum strain failure criterion for continuum shell elements/solid elements with anisotropic material. STRS3D Maximum stress failure criterion for continuum shell elements/solid elements with anisotropic material. CNTZ3D Cuntze failure criterion for continuum shell elements. No default
`TID`	Identification number of a TABLEMD entry that identifies the equivalent plastic strain (`Yi`) at the onset of damage vs temperature (`Xi`). 6
`Vi`	Material stress limits. `V1` Tensile stress limit in longitudinal direction. `V2` Compressive stress limit in longitudinal direction. `V3` Tensile stress limit in lateral direction. `V4` Compressive stress limit in lateral direction. `V5` In-plane shear stress limit. (Real > 0.0)
`Wi`	Parameters for failure criteria calculations. `W1` Failure envelope factor 12(-). `W2` Failure envelope factor 12(+) If blank, set to be equal to `W1`, `W1` and `W3` should be specified. `W3` Failure envelope factor 22(-). (Real > 0.0)

Comments

MID field may refer to MAT1, MAT2, MAT8, MAT9 or MAT9ORT entries.
For laminated shells (PCOMP/PCOMPP/PCOMPG).
V1, V2, through V5 specify material stress limits.

V1

Tensile stress limit in longitudinal direction

V2

Compressive stress limit in longitudinal direction

V3

Tensile stress limit in lateral direction

V4

Compressive stress limit in lateral direction

V5

In-plane shear stress limit

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

V1, V2 through V9 specify material stress limits.

V1

Tensile stress limit in 1-1 direction

V2

Compressive stress limit in 1-1 direction

V3

Tensile stress limit in 2-2 direction

V4

Compressive stress limit in 2-2 direction

V5

Tensile stress limit in 3-3 direction

V6

Compressive stress limit in 3-3 direction

V7

Shear stress limit in 1-2 direction

V8

Shear stress limit in 2-3 direction

V9

Shear stress limit in 1-3 direction

Coordinate system 1-2-3 are user-defined for continuum shell elements or solid elements with MAT9.
W1, W2 and W3 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(-)
- TSAI3D on anisotropic solid material
  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.
- 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, W2, and W3, corresponding to the three free curve parameters, $b_{⊥ | |}$ , $b_{⊥}^{T}$ and $b_{⊥ | |}^{τ}$ should be provided. The free 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)
  $0.0.5 < b_{⊥ | |} < 0.15, 1.0 < b_{⊥ |}^{T} < 1.6, 0 < b_{⊥ | |}^{τ} < 0.4$
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 and PLY entries (for PCOMPP). If different materials with different failure criteria are required to be defined for a single composite property, then MATF entry should be used.
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.
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).

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
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

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.

¹ Cuntze, R.G. and Freund, A., The predictive capability of failure mode concept-based strength criteria for multidirectional laminates in Failure Criteria in Fibre Reinforced Polymer Composites, 2004 QinetiQ Ltd. Published by Elsevier Ltd.