/PROP/TYPE21 (TSH_ORTH)

Block Format Keyword This property is used to define the orthotropic thick shell property set.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/PROP/TYPE21/prop_ID/unit_ID or /PROP/TSH_ORTH/prop_ID/unit_ID
prop_title
Isolid Ismstr     Icstr Inpts     dn
qa qb            
VX VY VZ Skew_ID Iorth    
ϕ                
Δ t min MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaqGuoGaam iDamaaBaaaleaaciGGTbGaaiyAaiaac6gaaeqaaaaa@3B70@                

Definitions

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)

 
Isolid Solid elements formulation flag.
= 0
Use value /DEF/SOLID.
= 14
HA8 locking-free 8-node thick shell, co-rotational, full integration, variable number of Gauss points in all directions.
= 15
HSEPH/PA6 thick shell (8-node and 6-node respectively), co-rotational, under integrated (1-point in-plan quadrature) with physical stabilization, variable number of integration points in thickness direction.

(Integer)

 
Ismstr Small strain formulation flag. 3
= -1
Automatically define the best value based on element type and material law.
= 0
Use value in /DEF_SOLID.
= 1
Small strain from time =0.
= 2
Full geometric nonlinearities with possible small strain formulation in Radioss Engine (/DT/Eltyp/Keyword3/Iflag)
= 3
Simplified small strain formulation from time =0 (non-objective formulation).
= 4 Default, if /DEF_SOLID is not defined
Full geometric nonlinearities (/DT/BRICK/CST has no effect).

(Integer)

 
Icstr Constant stress formulation flag. Only valid for Isolid = 14 (HA8 only). 1
= 001
Reduced stress integration in "t" direction.
= 010 (Default)
Reduced stress integration in "s" direction.
= 100
Reduced stress integration in "r" direction.

(Integer)

 
Inpts Number of integration points.
= j
1 < j < 9 for Isolid =15
= ijk
2 < i,j,k < 9 for Isolid =14

(Integer)

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.
 
dn Numerical damping for stabilization. Only valid for Isolid = 15.

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

 
VX X component for reference vector.

(Real)

 
VY Y component for reference vector.

(Real)

 
VZ Z component for reference vector.

(Real)

 
Skew_ID Skew identifier.

If the local skew has been defined, its X-axis replaces the reference vector (VX, VY, and VZ will be ignored).

(Integer)

 
Iorth Orthotropic system formulation flag for reference vector.
= 0 (Default)
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.

(Integer)

 
ϕ Angle of the first direction of orthotropy.

(Real)

[ deg ]
Δ t min MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaqGuoGaam iDamaaBaaaleaaciGGTbGaaiyAaiaac6gaaeqaaaaa@3B70@ Minimum time step.

Default = 106 (Real)

[ s ]

Example


prop_type21_example
Figure 1. Skew and Angle ϕ to Define the Material Direction (Fiber Direction) m1
#RADIOSS STARTER
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  1. SKEWS & FRAMES:
#---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                   1                   0
#                 X2                  Y2                  Z2
   -.408248290463863    .408248290463863    .816496580927726
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#-  2. 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----|
#-  3. GEOMETRICAL SETS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/TYPE21/1/2
TSH_ORTH example
#   Isolid    Ismstr                         Icstr     Inpts                                      dn
        14         0                           010       222                                       0
#                q_a                 q_b                   
                   0                   0                   
#                 Vx                  Vy                  Vz   skew_ID     Iorth          
                   0                   0                   0         1         0
#        Ortho_angle
                  90
#             dt_min
                   0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. Thickness direction:
    • By default, the element must be oriented so that the thickness direction of the thick shell is in the elements "s" direction.
    • However, when using Isolid=14 (HA8), a different thickness direction can be specified using the constant stress flag, Icstr.
      Note: Check the elements local system orientation using a pre-processor.


      Figure 2.
      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)
  2. Icstr - for reduced stress integration.
    For Isolid=14 (HA8) the reduced integration direction and thus thickness direction of the shell can be set by parameter Icstr. This parameter represents a 3-digit sequence of "0" and "1", which corresponds to standard r-s-t elemental coordinate system for solid elements.
    0
    No reduced stress integration is done in corresponding direction.
    1
    Reduced integration is used in this direction.

    For example:

    "010" means that reduced integration is used and the thickness direction corresponds to element axis "s".

  3. When using the automatic setting option Ismstr = Icpre = Iframe=-1, the values for these options are defined using the best options based on the element formulation, element type, and material. Alternatively, defining Ismstr = Icpre = Iframe=-2 will overwrite the values for these options defined in this property with the best value based on element type and material law. To see the values defined by Radioss, review the “PART ELEMENT/MATERIAL PARAMETER REVIEW” section of the Starter output file.
  4. Ismstr - Small strain formulation flag.
    • If the small strain option is set (Ismstr =1, 3), the strains and stresses used in material laws are engineering strains and stresses. Otherwise, they are true strains and stresses.
    • 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 Isolid =14, 15 Full geometric nonlinearities

      Ismstr = 2, 4

      Switch to small strain using element shape from cycle before negative volume.
  5. Isolid - Solid elements formulation flag.
    • When property is used with /MAT/LAW1 (ELAST), with Isolid =15 and number of integration points is different from one, number of integration points is set to 2 (enough to compute correct bending).
    • When using Isolid=15 with pentahedron elements, /PENTA6 elements are recommended but degenerated /BRICK elements can also be used.
  6. Othotropy in local coordinate system.
    • The thick shell orthotropy is planar and the third orthotropy direction is coincident with the normal to the shell plane.
    • Global vector V MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaCOvaaaa@36D5@ or skew_ID is used to define the othotropy direction.
    • ϕ is the angle between the first direction of orthotropy and projection of reference vector on the shell mean plane (r and t). It is given in degrees.


      Figure 3.
  7. Output for post-processing.
    • For post-processing solid element stress, refer to /ANIM/BRICK/TENS/STRESS and /H3D/SOLID/TENS/STRESS for animation and /TH/BRICK for plot files.