/PROP/TYPE9 (SH_ORTH)

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

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/PROP/TYPE9/prop_ID/unit_ID or /PROP/SH_ORTH/prop_ID/unit_ID
prop_title
Ishell Ismstr Ish3n Idril     P_thickfail    
hm hf hr dm dn
N Istrain Thick Ashear   Ithick Iplas  
VX VY VZ ϕ      

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)

 
Ishell Shell element formulation flag. 1
= 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)

 
Ismstr Shell small strain formulation flag. 2
= 0
Use value in /DEF_SHELL.
= 1
Small strain from time = 0 (formulation compatible with all other formulation flags).
= 2 Default, if /DEF_SHELL is not defined.
Full geometric nonlinearities with possible small strain formulation activation in Radioss Engine (option /DT/SHELL/CST).
= 3
Old small strain formulation (only compatible with hourglass type 2).
= 4
Full geometric nonlinearities (in Radioss Engine, option /DT/SHELL/CST has no effect).
= 11
Total small strain from time = 0.

(Integer)

 
Ish3n 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, which based on DTK12 of BATOZ (refer to Element Library in the Theory Manual).

(Integer)

 
Idril Drilling degree of freedom stiffness flag. 7
= 0
Use value in /DEF_SHELL.
= 1
Yes.
2 Default, if /DEF_SHELL is not defined.
No.

(Integer)

 
P_thickfail Percentage of through thickness integration points that must fail before the element is deleted. 9 10

0.0 P _ t h i c k f a i l 1.0 (Real)

 
hm Shell membrane hourglass coefficient. 3

Default = 0.01

Default = 0.1 for hourglass type 3 (Ishell =3)

(Real)

 
hf Shell out-of-plane hourglass. 3

Default = 0.01

Default = 0.1 for hourglass type 3 (Ishell =3)

(Real)

 
hr Shell rotation hourglass coefficient. 3

Default = 0.01

Default = 0.1 for hourglass type 3 (Ishell =3)

(Real)

 
dm Shell Membrane Damping

It is only active for Material Laws 19, 25, 32 and 36.

Default =1.5% for Ishell =24 (QEPH)+LAW19, 32 and 36.

Default =5.0% for Ishell =24 (QEPH)+LAW25

Default =0.0% for Ishell =12 (QBAT)

Default =5.0% for Ishell =1,2,3,4 (Q4)+LAW25

Default =25.0% for Ishell =1,2,3,4 (Q4)+LAW19

Default =0.0% for Ishell =1,2,3,4 (Q4)+LAW32 and 36

(Real)

 
dn Shell numerical damping. 4

It only used for Ishell =12 and 24.

Default =1.5% for Ishell =24 (QEPH)

Default =0.1% for Ishell =12 (QBAT)

Default =0.01% for Ish3n =30 (DKT18)

(Real)

 
N Number of integration points through the thickness 1 < N < 10.

Default set to 1 (Integer)

 
Istrain Compute strains for post-processing flag.
= 0
Use value in /DEF_SHELL.
= 1 Default, if /DEF_SHELL is not defined
Yes.
= 2
No.

(Integer)

 
Thick Shell thickness.

(Real)

[ m ]
Ashear Shear factor.

Default is Reissner value: 5/6 (Real)

 
Ithick Shell resultant stresses calculation flag.
= 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)

 
Iplas Shell plane stress plasticity flag. 6
It is available for Material Laws 2, 22, 32, 36 and 43.
= 0
Use value in /DEF_SHELL.
= 1
Iterative projection with three Newton iterations.
= 2 Default, if /DEF_SHELL is not defined
Radial return.

(Integer)

 
VX X component. 8

Default = 1.0 (Real)

 
VY Y component. 8

Default = 0.0 (Real)

 
VZ Z component. 8

Default = 0.0 (Real)

 
ϕ Angle. 8

Default = 0.0 (Real)

[ deg ]

Example

There are 3 integration points through the shell thickness. Material direction m1 (fiber direction) defined with vector V and angle ϕ .

prop_type9_example
Figure 1.
#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----|
#-  2. GEOMETRICAL SETS:
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
/PROP/SH_ORTH/2/2
SH_ORTH example
#   Ishell    Ismstr     Ish3n    Idrill
        12         0         0         1
#                 hm                  hf                  hr                  dm                  dn
                   0                   0                   0                  .1                  .1
#        N   Istrain               Thick              Ashear              Ithick     Iplas
         3         0                 1.8                   0                   1         1
#                 Vx                  Vy                  Vz                 Phi
                   1                   0                   1                  45
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|

Comments

  1. Ishell. Ish3n – 4-node and 3-node shell formulation flag
    • Ishell =1,2,3,4 (Q4): original 4 node Radioss shell with hourglass perturbation stabilization.
    • Ishell =24 (QEPH): formulation with hourglass physical stabilization for general use.
    • Ishell =12 (QBAT): modified BATOZ Q4γ24 shell with four Gauss integration points and reduced integration for in-plane shear. No hourglass control is needed for this shell.
    • Ish3n =30 (DKT18): BATOZ DKT18 thin shell with three Hammer integration points.
    • Flag Ishell =2 is incompatible with one integration point for shell element.
  2. Ish3n - Small strain formulation
    • Small strain formulation is activated from time t= 0, if Ismstr = 1, 3 or 11. It may be used for a faster preliminary analysis, but the accuracy of results is not ensured. Any shell for which Δ t< Δ t min can be switched to a small strain formulation by Radioss Engine option /DT/SHELL/CST, except if Ismstr = 4 or 11.
    • If Ismstr =1, 3 or 11, the strains and stresses which are given in material laws are engineering strains and stresses; otherwise they are true strains and stresses.
    • Ismstr =11 has been developed to improve the robustness for Airbag models; actually it is only compatible with Law 19 and with all quadrilateral shells and standard C0 tria. For Q4 shell using reference state coordinates, when Ismstr = 1, it will be set automatically to Ismstr = 11.
  3. hm, hf, and hr - Hourglass coefficients
    • hm, hf, and hr are only used for Q4 shells (Ishell=1,2,3,4). They must have a value between 0 and 0.05.
    • For Ishell=3, default values of hm and hr are 0.1 with larger values possible.
  4. dn - Shell numerical damping coefficient
    • dn is only used for Ishell =12 and 24 and Ish3n=30:
      • for Ishell = 24, dn is used for hourglass stress calculation
      • for Ishell = =12 (QBAT) dn is used for all stress terms, except transvers shear
      • for Ish3n=30 (DKT18) dn is only used for membrane
  5. Ithick - Shell resultant stresses calculation flag
    • Flag Ithick is automatically set to 1 for /MAT/LAW32 (HILL).
    • If Ithick=1, the small strain option is automatically deactivated in the corresponding type of element.
  6. Iplas - Shell plane stress plasticity flag
    • It is recommended to use Iplas = 1, if Ithick = 1.
    • If Iplas =1, the small strain option is automatically deactivated in the corresponding type of element.
  7. Idril - Drilling degree of freedom stiffness flag
    • Drilling DOF stiffness is recommended for implicit solutions especially for Riks method and bending dominated problems.
    • Idril is available for QEPH, QBAT (Ishell = 12 and 24), and standard triangle (C0) shell elements (Ish3n = 1 and 2).
  8. Orthotropy in local coordinate system:
    • Orthotropic direction defined with global vector V (components defined in Line 6) and angle ϕ (angle in degree).
    • Projection of vector V on shell element plane becomes the vector V . Next, the element's orthotropic direction (direction 1) vector V is turned ϕ degrees; where, positive rotation is based on the shell normal n MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaCOBaaaa@36ED@ .

      prop_type9_v10
      Figure 2.
    • In case of reference metrics, the orientation for directions of anisotropy must be defined with the reference geometry, not the initial one.
  9. P_thickfail parameter is not compatible with failure defined within the material law itself, such as plastic failure strain in LAW36.
  10. Element deletion rules used with /FAIL models:
    • Under-integrated elements (Belytchko, QEPH, DKT18):
      • If more than one failure model is applied to the shell material, or P_thickfail=0 (blank), the value of P_thickfail is calculated individually from each failure model settings.
        Example:
        Ifail_sh = 1
        One integration point failure sufficient to delete element, then P_thickfail= 1.0 e-6
        Ifail_sh = 2
        All integration points failure is necessary to delete the element, thenP_thickfail= 1.0
      • If only one failure model is applied to the material, the P_thickfail value from the property is taken by default and overwrites local Ifail_sh settings from the failure model.
    • Fully integrated shells (Batoz, DKT_S3):
      • The rule described for under-integrated shells applies to each Gauss point separately. P_thickfail ratio is checked for all integration points in thickness for each in-plane Gauss point. The element is deleted only when all Gauss points reach P_thickfail ratio criteria.