/PROP/TYPE6 (SOL

Block Format Keyword

/PROP/TYPE6 - Orthotropic Solid Property Set

Description

Describes the orthotropic solid property set. This property set is used to define the fiber plane for LAW14, the steel reinforcement direction for /MAT/LAW24 (CONC) or the cell direction for /MAT/LAW28 (HONEYCOMB). This property is only available for 8-node linear solid elements (/BRICK), tetrahedron elements (/TETRA4 and/TETRA10), and 2D solid elements (/QUAD). Quadratic bricks (/BRIC20 and /SHEL16) and pentahedron elements (/PENTA6) are not compatible with this property.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/PROP/TYPE6/prop_ID/unit_ID or /PROP/SOL_ORTH/prop_ID/unit_ID
prop_title
Isolid	Ismstr		Icpre		Inpts		Iframe	dn
qa		qb		h
Vx		Vy		Vz		skew_ID	Ip	Iorth

		Istrain	IHKT

Field	Contents	SI Unit Example
prop_ID	Property identifier (Integer, maximum 10 digits)
unit_ID	Optional unit identifier (Integer, maximum 10 digits)
prop_title	Property title (Character, maximum 100 characters)
Isolid	Solid elements formulation flag For tet4 and tet10 only Isolid =1 is available. (Integer) = 0: default, set to value defined in /DEF_SOLID = 1: Standard 8-node solid element, one integration point. Viscous hourglass formulation with orthogonal and rigid deformation modes compensation (Belytschko). = 2: Standard 8-node solid element, one integration point. Viscous hourglass formulation without orthogonality (Hallquist). = 14: HA8 locking-free 8-node solid element, co-rotational, full integration, variable number of Gauss points. = 17: H8C compatible solid full integration formulation = 24: HEPH 8-node solid element. Co-rotational, under-integrated (1 Gauss point) with physical stabilization
Ismstr	Small strain formulation flag (Comments 1 and 22) (Integer) = 0: default, set to value defined in /DEF_SOLID = 1: small strain from time = 0 = 2: full geometric nonlinearities with possible small strain formulation in RADIOSS Engine (/DT/BRICK/CST) = 3: simplified small strain formulation from time=0 (non-objective formulation) = 4: full geometric nonlinearities (/DT/BRICK/CST has no effect) = 10: Lagrange type total strain.
Icpre	Constant pressure formulation flag (Comments 8 and 9) (Integer) = 0: default value = 1: reduced pressure integration = 2: variable state between Icpre =3 and Icpre =1 in function of plasticity state = 3: no reduced pressure integration
Inpts	Number of integration points (only for Isolid =14) (Integer) = ijk: 2 < i,j,k < 9 for Isolid =14 where: i = number of integration points in r direction j = number of integration points in s direction k = number of integration points in t direction
Iframe	Element coordinate system formulation flag (only for quad and standard and compatible 8-node bricks: Isolid = 1, 2, or 17) (Integer) = 0: default set to 1 = 1: non co-rotational formulation = 2: co-rotational formulation
dn	Numerical damping for stabilization (Isolid =24 only) Default = 0.1 (Real)
qa	Quadratic bulk viscosity Default = 1.10 (Real) Default = 0.0 for /MAT/LAW70
qb	Linear bulk viscosity Default = 0.05 (Real) Default = 0.0 for /MAT/LAW70
h	Hourglass viscosity coefficient Default = 0.10 (Real) must be 0.0 < h < 0.15
Vx	X component for reference vector (Comment 18) (Real)
Vy	Y component for reference vector (Comment 18) (Real)
Vz	Z component for reference vector (Comment 18) (Real)
skew_ID	Skew frame identifier defining orthotropic directions (Integer)
Ip	Reference plane (Integer) = 0: use skew_ID (skew_ID value must be different from 0) (Comment 20) = 1: plane (r,s) + angle (Comment 16) = 2: plane (s,t) + angle (Comment 16) = 3: plane (t,r) + angle (Comment 16) = 11: plane (r,s) + orthogonal projection of reference vector (Vx, Vy, and Vz) on plane (r,s) = 12: plane (s,t) + orthogonal projection of reference vector (Vx, Vy, and Vz) on plane (s,t) = 13: plane (t,r) + orthogonal projection of reference vector (Vx, Vy, and Vz) on plane (t,r)
Iorth	Orthotropic system formulation flag (Integer) = 0: the first axis of orthotropy is maintained at constant angle with respect to the orthonormal co-rotational element coordinate system. = 1: the first orthotropy direction is constant with respect to a non-orthonormal isoparametric coordinates.
	Orthotropic angle with first reference plane direction (Real)
	Minimum time step Default = 106 (Real)
Istrain	Compute strain post-processing flag (Integer) = 0: default set to value defined in /DEF_SOLID = 1: yes = 2: no
IHKT	Hourglass tangent modulus flag (Isolid =24 only) (Integer) = 0: default, set to 1 = 1: elastic modulus or numerical tangent modulus estimation = 2: advanced tangent modulus estimation

Uses skew

prop_type6_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

kg mm ms

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/SKEW/FIX/1

New SKEW 1

# OX OY OZ

0 100 0

# X1 Y1 Z1

1 0 -1

# X2 Y2 Z2

0 1 0

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#- 2. GEOMETRICAL SETS:

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/PROP/SOL_ORTH/1/2

SOL_ORTH example

# Isolid Ismstr Icpre Inpts Iframe dn

14 0 1 0 0 0

# q_a q_b h

0 0 0

# Vx Vy Vz skew_ID Ip Iorth

0 0 0 1 0 0

# phi

# dt_min Istrain I_HKT

0 0 0

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#enddata

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Uses Ip =1 and angle to get same material direction (fiber direction) m1.

prop_type6_example2

#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

kg mm ms

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

/PROP/SOL_ORTH/1/2

SOL_ORTH example

# Isolid Ismstr Icpre Inpts Iframe dn

14 0 1 0 0 0

# q_a q_b h

0 0 0

# Vx Vy Vz skew_ID Ip Iorth

0 0 0 0 1 0

# phi

# dt_min Istrain I_HKT

0 0 0

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

#enddata

#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

1.	Small strain:

If the small strain option is set, the strains and stresses used in material laws are engineering strains and stresses. Otherwise, they are true strains and stresses.

The RADIOSS Engine option /DT/BRICK/CST will only work for brick property sets with Ismstr =2. The flag Ismstr =10 is only compatible with material laws using total strain formulation (for example, Laws 1, 28, 38, 42 and 50). The left Cauchy-Green strain is used for /MAT/LAW1 (ELAST), /MAT/LAW38 (VISC_TAB) and /MAT/LAW42 (OGDEN), otherwise, the Green-Lagrange strain.

2.	Co-rotational formulation:

For Isolid =1 or 2, and Iframe =2, the stress tensor is computed in a co-rotational coordinate system. This formulation is more accurate if large rotations are involved, at the expense of higher computation cost. It is recommended in case of elastic or visco-elastic problems with important shear deformations. Co-rotational formulation is compatible with 8 node bricks. Co-rotational formulation is also compatible with bi-dimensional and axisymmetric analysis (/QUAD) element).

3.	If the small strain option is set to 1 or 3, the strains and stresses which are given in material laws are engineering strains and stresses; otherwise they are true strains and stresses.

4.	HEPH elements: hourglass formulation is similar to QEPH shell elements.

5.	HA8: Locking-free general solid formulation. example: Inpts =222 is an 8 Gauss integration points solid. HA8 formulation is compatible with all orthotropic and isotropic material laws.

6.	An HA8 solid element should use under integrated pressure (Icpre =1 in case of elastic or visco-elastic law; Icpre =2 in case of elasto-plastic law).

7.	If Isolid =17, brick deviatoric behavior is computed using 8 Gauss points, but the bulk behavior can be chosen with Icpre, and compatible with all solid type material laws.

8.	Flag Icpre is only used for HA8, H8C and HEPH (Isolid =14, 17, or 24).

9.	The default value of Icpre is:

•	Icpre =3 is the default value for Isolid =14 (HA8) and Isolid =24 (HEPH);

•	Icpre =1 is the default value for Isolid =17 (H8C).

10.	Flag Icpre = 2 is only available for elasto-plastic material law.

11.	Numerical damping dn is only used in hourglass stress calculation for HEPH (Isolid = 24). If dn uses the same value as h (hourglass viscosity coefficient for Isolid =1 or 2), the damping value is about times than Isolid =1 or 2.

12.	In animation files, the stress components SIGX, SIGY, SIGZ, SIGXY, SIGYZ, and SIGXZ are expressed in global coordinate system with the exception of cases when elements are using co-rotational formulation:

•	Iframe =2 with Isolid =1, 2, 17

•	Isolid =14, 24

In these cases the stress output is represented in material orthotropic coordinate system defined in /PROP/SOL_ORTH.

13.	In plot files, the stress components SX, SY, SZ, SXY, SYZ, and SXZ are expressed in the global frame and the stress tensors components LSX, LSY, LSZ, LSXY, LSYZ, and LSXZ are expressed in the orthotropic frame (refer to /TH/BRICK for post-processing solid element stress in plot files).

14.

For 2D solid elements (/QUAD), when global formulation is used, orthotropic angle is defined with respect to the first direction of the orthogonalized isoparametric frame. When the co-rotational formulation is used, the orthotropic angle is defined with respect to the first direction of the co-rotational frame and the orthotropic frame keeps the same orientation with respect to the co-rotating (local) frame: orthotropic frame is co-rotating.

prop_sol_orth_quad

15.	For 8 node bricks (Isolid =0, 1, or 2), 4-node tetrahedron and 10-node tetrahedron, the orthotropic system rotates like the orthogonalized isoparametric system. Attention must be paid to the orientation of the orthotropic system in case of large shear.

clip0100

r, s, t: isoparametric frame

r: center of (1, 2, 6, 5) to center of (4, 3, 7, 8)

s: center of (1, 2, 3, 4) to center of (5, 6, 7, 8)

t: center of (1, 4, 8, 5) to center of (2, 3, 7, 6)

clip0101

16.	If Ip = 1, 2 or 3, the orthotropic system initial orientation is defined with respect to the initial orthogonalized isoparametric system, as follows:

starter_prop_sol-orth

starter_prop_sol-orth_ip2

17.	For bricks, if Iframe = 2, the orthotropic system rotates like the co-rotational system. A co-rotational system is an orthogonalization of isoparametric systems r, s, t that has the same orientation whatever the permutation of r, s, t.

If Ip = 1, 2 or 3, the orthotropic system initial orientation is defined the same way as for bricks, Isolid = 0, 1 or 2 (that is with respect to the orthogonalized isoparametric system), and knowledge of the co-rotational system orientation is unnecessary to input the orthotropic system initial orientation.

18.	Global vector V may be used to define the orthotropy direction, instead of skew_ID.

19.	If Ip = 11, 12 or 13, if reference vector is orthogonal to plane, the first axis of the plane is taken as orthotropy direction.

20.	If Ip = 0 and skew_ID ≠ 0, no reference plane is used; skew is taken directly as the orthotropic system (in this case r =x, s =y, and t =z).

21.	It is recommended to use IHKT = 2 with LAW24, if the damage effect is taken into account in hourglass stress compute. For elasto-plastic type laws, IHKT = 2 will get a tighter yield stress criterion for hourglass stress compute.

22.	Starting with version 2017, Lagrangian elements whose volume becomes negative during a simulation will automatically switch strain formulations to allow the simulation to continue. When this occurs, a WARNING message will be printed in the Engine output file. The following options are supported.

Element Type	Element Formulation	Strain Formulation	Negative Volume handling method
/BRICK /TETRA4 (Itetra = 0) /TETRA10	Isolid =1, 2, 14, 17, 24	Full geometric nonlinearities Ismstr = 2, 4	Switch to small strain using element shape from cycle before negative volume
/BRICK /TETRA4 (Itetra = 0) /TETRA10	Isolid =1, 2, 14, 17, 24	Lagrange type total strain Ismstr = 10	Lagrange total strain with element shape at time=0.0

/PROP/TYPE6 (SOL_ORTH)

/PROP/TYPE6 (SOL_ORTH)

/PROP/TYPE6 (SOL_ORTH)