/PROP/TYPE16 (SH_FABR)

Block Format Keyword This property is used to define the anisotropic layered shell property. This property is currently only compatible with elastic anisotropic fabric (/MAT/LAW58 (FABR_A)).

Format

(1)	(2)	(3)	(5)	(7)	(8)	(9)	(10)
/PROP/TYPE16/`prop_ID`/`unit_ID` or /PROP/SH_FABR/`prop_ID`/`unit_ID`
`prop_title`
`I`_shell	`I`_smstr	`I`_sh3n		`P_thick`_fail
`h`_m		`h`_f	`h`_r	`d`_m		`d`_n
`N`		`Thick`	`A`_shear		`I`_thick
`V`_X		`V`_Y	`V`_Z	`skew_ID`	`I`_pos		`I`_P

Each layer (integration point) per line:

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
$ϕ_{i}$		$α_{1}$		`t`_i		`Z`_i		`mat_ID`_i

Definition

Field	Contents	SI Unit Example
`prop_ID`	Property identifier. (Integer, maximum 10 digits)
`unit_ID`	Unit Identifier. (Integer, maximum 10 digits)
`prop_title`	Property title. (Character, maximum 100 characters)
`I`_shell	Shell element formulation flag. = 0 Use value in /DEF_SHELL. = 1 Default, if /DEF_SHELL is not defined Q4, visco-elastic hourglass modes orthogonal to deformation and rigid modes (Belytschko). = 2 Q4, visco-elastic hourglass without orthogonality (Hallquist). = 3 Q4, elasto-plastic hourglass with orthogonality. = 4 Q4 with improved type 1 formulation (orthogonalization for warped elements). = 12 QBAT shell formulation. = 24 QEPH shell formulation. (Integer)
`I`_smstr	Shell small strain formulation flag. = -1 Automatically set the best value according to element type and material law. = 4 (Default) Full geometric nonlinearities (in Radioss Engine, option /DT/SHELL/CST has no effect). (Integer)
`I`_sh3n	3 node shell element formulation flag. = 0 Use value in /DEF_SHELL. = 1 Standard triangle (C0). = 2 Default, if /DEF_SHELL is not defined Standard triangle (C0) with modification for large rotation. = 30 DKT18 = 31 DKT_S3 (Integer)
`P_thick`_fail	Fraction of failed thickness for shell element deletion. 7 $0.0 \leq P_t h i c k_{f a i l} \leq 1.0$ Fraction of failed thickness. -1.0 ≤ `P_thick`_fail ≤ 0 Fraction of failed layers. $0.0 \leq P_t h i c k_{f a i l} \leq 1.0$ (Real) Default = 1.0 (Real)
`h`_m	Shell membrane hourglass coefficient. Only used when `I`_shell =1, 2, 3, 4 Default = 0.01 Default = 0.1 for `I`_shell =3 (Real)
`h`_f	Shell out-of-plane hourglass. Only used when `I`_shell =1, 2, 3, 4 Default = 0.01 (Real)
`h`_r	Shell rotation hourglass coefficient. Only used when `I`_shell =1, 2, 3, 4 Default = 0.01 Default = 0.1 for `I`_shell =3 (Real)
`d`_m	Shell membrane damping. Used only for material LAW58. Default =0.075 for `I`_shell =1, 2, 3, 4 Default= 0.15 for `I`_shell =24 Default =0.2 for `I`_shell =12 Default = 0.0 for all 3 node shells (Real)
`d`_n	Shell numerical damping. 9 Only used for `I`_shell =12, 24 and `I`_sh3n = 30 Default =0.015 for `I`_shell =24 (QEPH) Default =0.001 for `I`_shell =12 (QBAT) Default =0.0001 for `I`_sh3n =30 (DKT18) (Real)
`N`	Number of layers, with $1 \leq N \leq 100$ . 6 Default = 1 (Integer)
`Thick`	Shell thickness. (Real)	$[m]$
`A`_shear	Shear factor. Default is Reissner value: 5/6 (Real)
`I`_thick	Shell resultant stresses calculation flag. = -1 Automatically set the best value according to element type and material law. = 0 Use value in /DEF_SHELL. = 1 Thickness change is taken into account. = 2 Default, if /DEF_SHELL is not defined Thickness is constant . (Integer)
`V`_X	X component for reference vector. 3 Default = 1.0 (Real)
`V`_Y	Y component for reference vector. Default = 0.0 (Real)
`V`_Z	Z component for reference vector. Default = 0.0 (Real)
`skew_ID`	Skew identifier for reference vector. 3 Default = 0 (Integer)
`I`_pos	Layer positioning flag for reference vector. 4 = 0 (Default) Layer positions `Z`_i are automatically calculated with regard to layer thicknesses. = 1 All layer positions `Z`_i must be user-defined. Default = 0 (Integer)
`I`_P	Reference direction in shell plane. 3 = 0 (Default) Use 1^st direction of `skew_ID` or vector $V$ (if `skew_ID` is not defined) projected on the shell element. = 20 Defined from element connectivity (N1,N2) of the shell element. = 22 Defined from 1^st direction of `skew_ID` projected on the shell element and angle phi. (Vector $V$ is ignored). = 23 Defined from vector product of vector $V$ and the shell element normal direction $n$ (`skew_ID` is ignored). (Integer)
$ϕ_{i}$	Angle $ϕ_{i}$ of 1st local axis for layer `i`. 3 (Real)	$[\deg]$
$α_{i}$	Angle between first and second axis. 3 Default = 90.0 (Real)	$[\deg]$
`t`_i	Thickness `t`_i of layer `i`. (Real)	$[m]$
`Z`_i	Z position of layer i (`Z`_i defines the position of the middle of the layer). Default = 0.0 (Real)	$[m]$
`mat_ID`_i	Material identifier for layer `i`. Same material should be used for all layers. (Integer)

Example

#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  1. LOCAL_UNIT_SYSTEm:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/UNIT/2
unit for PROP
#              MUNIT               LUNIT               TUNIT
                  Mg                  mm                   s
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. GEOMETRICAL SETS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/TYPE16/2/2
prop type 16
#   Ishell    Ismstr     Ish3n                                       Pthick_fail
         0         0         0                                                 0
#                 hm                  hf                  hr                  dm
                   0                   0                   0                   0
#        N                         Thick              Ashear              Ithick
         3                           1.6                   0                   0
#                 Vx                  Vy                  Vz   skew_ID      Ipos                  Ip
                   1                   0                   1         0         0                   0
#                Phi               Alpha                  Ti                  Zi   mat_IDi
                  45                  90                  .5                             1          
                  90                  90                  .6                             2          
                 -45                  90                  .5                             1          
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

I_shell – 4-node shell formulation flag
The hourglass formulation is visco-elastic for Q4 shells (I_shell=1,2,3,4).
h_m, h_f, and h_r - Hourglass coefficients
- h_m, h_f, and h_r are used only for Q4 shells (I_shell=1,2,3,4). They must have a value between 0 and 0.05.
- For I_shell=3, default values of h_m and h_r are 0.1 with larger values possible.
Anisotropy direction definition.
The reference vector $V'$ is projection of the input vector $V$ on the shell element surface and defined as following according to the flag I_P:
- If I_P=0 and skew_ID = 0, the vector $V$ is defined with V_X, V_Y and V_Z.
- If I_P=0 and skew_ID ≠ 0, the vector $V$ is the first direction (local X) of the local coordinate system skew_ID.
- If I_P = 20, the vector $V$ is defined with the node N1 and N2 of the shell elements.
  
  Figure 1. I_P = 20
- If I_P = 22, the vector $V$ is the first direction (local X) of the local coordinate system skew_ID. Vector components V_X, V_Y and V_Z are ignored.
  
  Figure 2. I_P = 22
- If I_P = 23, the vector $V$ is defined with V_X, V_Y and V_Z. The reference vector $V'$ is the product of vector $V$ and shell element normal direction $n$ . Local coordinate system skew_ID is ignored.
  
  Figure 3. I_P = 23
Then for each layer, the 1^st material direction (m1) is vector $V^{'}$ turned $ϕ_{i}$ degrees (turns positive direction around shell normal $n$ ).

Figure 4.
The hierarchy order to define the reference vector $V$ is:
- initial state card (/INISHE/ORTHO)
- shell property
In case of reference metrics, the orientation for directions of anisotropy must be defined with the reference geometry, not the initial one.

The 2^nd material direction m2 is derived from direction m1 with the angle $α_{i}$ .

If $α_{i} = 90 °$ , the layer is orthotropic.
I_pos – Layer position
I_pos= 0: layer positions are calculated automatically.
If (1)
$T h i c k \neq \sum_{i}^{N} t_{i}$
- A warning message is displayed
- Individual layer thickness will be adjusted to new layer thickness $t_{i}^{n e w}$ with:(2)
  $T h i c k = \sum_{i}^{N} t_{i}^{n e w}$
  
  Here "Thick" and $t_{i}$ are the shell thickness and layer thickness which are specified in input.
  
  Figure 5.
- I_pos = 1: all layer positions in the element thickness are user-defined (with $t_{i}$ and $Z_{i}$ ).
  - “Thick” is not checked, as it does not need to be equal to the sum of layer thickness.
  - Multiple layers are allowed to have the same space position.
For more details, refer to Layer thickness and position calculation. in FAQs.
The material law number given in /PART will be used to define the density and Young’s modulus which then is used to calculate the time step and interface stiffness.
Each i layer has only 1 integration point through its thickness.
Element deletion rules used with P_thick_fail and failure models:
- Only P_thick_fail defined in the property is considered to trigger the element failure.
  - P_thick_fail > 0 defines a fraction of failed thickness. This uses the amount of element global thickness assigned to each layer.
  - P_thick_fail < 0 defines a ratio of failed layers. This uses the number of layers.
- the P_thick_fail defined in failure model(s) (/FAIL) are not used.
- For fully-integrated shells (I_shell=12), the rules described above for under-integrated shells applies to each Gauss point separately. P_thick_fail criterion is checked for all layers thickness for each in-plane Gauss point. The element is deleted only when all Gauss points reach P_thick_fail criterion.
- P_thick_fail rules are not used with failure models defined inside the material laws. It is used only for the failure model defined with /FAIL.
Thickness is constant for material /MAT/LAW58. Flag I_thick is not used for this material.
Shell numerical damping coefficient d_n is only used for I_shell=12, 24 and I_sh3n=30:
- I_shell =24 (QEPH) d_n is used for hourglass stress calculation.
- I_shell =12 (QBAT) d_n is used for all stress terms.
- I_sh3n =30 (DKT18) d_n is used for all stress terms, except transverse shear.