/PROP/TYPE1 (SHELL)
Block Format Keyword Describes the shell property set which is used for 3-node or 4-node shell element. Belytschko, QBAT or QEPH shell formulation are available.
Format
(1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) |
---|---|---|---|---|---|---|---|---|---|
/PROP/TYPE1/prop_ID/unit_ID or /PROP/SHELL/prop_ID/unit_ID | |||||||||
prop_title | |||||||||
Ishell | Ismstr | Ish3n | Idrill | P_thickfail | |||||
hm | hf | hr | dm | dn | |||||
N | Thick | Ashear | Ithick | Iplas | |||||
Ipos |
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) |
|
Ishell | 4 node shell element
formulation flag.
(Integer) |
|
Ismstr | Shell small strain
formulation flag. 4
(Integer) |
|
Ish3n | 3 node shell element
formulation flag.
(Integer) |
|
Idrill | Drilling degree of freedom
stiffness flag. 3
(Integer) |
|
P_thickfail | Fraction of failed
thickness for shell element deletion. 11
Default = 1.0 (Real) |
|
hm | Shell membrane hourglass
coefficient. 5 Only used when Ishell=1, 2, 3, 4. Default = 0.01 for Ishell =1, 2, 4. Default = 0.1 for Ishell = 3. (Real) |
|
hf | Shell out-of-plane
hourglass. 5 Only used when Ishell=1, 2, 3, 4. Default = 0.01 (Real) |
|
hr | Shell rotation hourglass
coefficient. 5 Only used when Ishell=1, 2, 3, 4. Default = 0.01 for Ishell =1, 2, 4. Default = 0.1 for Ishell = 3. (Real) |
|
dm | Shell Membrane Damping For default values, refer to the table in Comment 7. (Real) |
|
dn | Shell numerical damping.
6 It is only used for Ishell =12, 24 and Ish3n = 30 Default =0.015 for Ishell =24 (QEPH) Default =0.001 for Ishell =12 (QBAT) Default =0.0001 for Ish3n =30 (DKT18) (Real) |
|
N | Number of integration
points through the thickness with 0 < N <
10. 10
(Integer) |
|
Thick | Shell
thickness. (Real) |
|
Ashear | Shear factor. Default is Reissner value: 5/6 (Real) |
|
Ithick | Shell resultant stresses
calculation flag. 8
(Integer) |
|
Iplas | Shell plane stress
plasticity flag. 9 It is available for material
laws 2, 22, 27 and 36.
(Integer) |
|
Ipos | Mid shell positioning flag. 12
(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
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/SHELL/1/2
Shell_1mm
# Ishell Ismstr Ish3n Idrill P_thick_fail
24 0 0 0 0
# hm hf hr dm dn
0 0 0 0 0
# N Istrain Thick Ashear Ithick Iplas
5 0 1 0 1 1
# Ipos
0
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
#enddata
#---1----|----2----|----3----|----4----|----5----|----6----|----7----|----8----|----9----|---10----|
Comments
- Ishell - Shell small strain
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
- Ishell=2 is incompatible with one integration point (through thickness) for shell element
- Ish3n - 3 node shell element
formulation flag
- Ish3n=30 (DKT18): BATOZ DKT18 thin shell with three Hammer integration points
- Idrill - Drilling degree of freedom
stiffness flag
- Drilling DOF stiffness is recommended for implicit solutions especially for Riks method and bending dominated problems
- Idrill is available for QEPH, QBAT (Ishell =12, 24), and standard triangle (C0) shell elements (Ish3n = 1, 2)
- Ismstr - Small strain formulation
- Small strain formulation is activated from time t=0, if Ismstr =1 or 3. It may be used for a faster preliminary analysis, but the accuracy of the results is not ensured.
- Any shell for which can be switched to a small strain formulation by Radioss Engine option /DT/SHELL/CST; except if Ismstr =4.
- 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.
- Ismstr =10 is only compatible with these material laws 42, 62, 69, and 82 that use total strain formulation. Generally, the Left Cauchy-Green strain is used. For User laws, the deformation gradient tensor and the right stretch tensor may be used.
- hm, hf, and hr - Hourglass coefficients
- Are only used for Q4 shells (Ishell=1,2,3,4). They must have a value between 0 and 0.05.
- For Ishell=3, the default values of hm and hr are 0.1 with larger values possible.
- dn - Shell
numerical damping coefficient
- dn is only used for Ishell =12, 24 and Ish3n = 30
- Ishell =24 (QEPH) dn is used for hourglass stress calculation
- Ishell =12 (QBAT) dn is used for all stress terms, except transvers shear
- Ish3n =30 (DKT18) dn is only used for membrane
- dn is only used for Ishell =12, 24 and Ish3n = 30
- Default value for
numerical damping coefficient
dm.
dm Ishell= 1, 2, 3, 4 (Q4) 0.05 for LAW27 0.0 for LAW32, 36
Ishell=12 (QBAT) 0.0 for LAW2, 27, 32, 36 Ishell=24 (QEPH) 0.015 for all other material Ish3n= 1, 2, 31 0.0 Ish3n=30 (DKT18) 0.0 Any Ishell, Ish3n 0.05 for LAW65 - Ithick - Shell resultant stresses
calculation flag
- Ithick is automatically set to 1 for material LAW32
- Ithick =1, the small strain option is automatically deactivated in the corresponding type of element
- 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
- Global integration,
N=0
- Global integration is only compatible with material LAW1.
- Failure models are not available with global integration for shells.
- State files (/STATE/DT which creates /INISHE and /INISH3N) are not compatible with global integration.
- Automatically set to N=3 for the other material laws.
- Element deletion rules
used with P_thickfail and
failure models:
- P_thickfail defined in
both the property and in the failure model(s) (/FAIL)
are considered to trigger the element failure.
- P_thickfail > 0 defines a fraction of failed thickness. This uses the amount of thickness assigned to each integration point.
- P_thickfail < 0 defines a ratio of failed integration points. This uses the number of integration point.
- Minimum of the absolute value defined in the shell property or in the failure criterion card is used to trigger the element failure.
- For fully-integrated shells (Ishell=12), the rules described above for under-integrated shells applies to each Gauss point separately. P_thickfail criterion is checked for all integration point thickness for each in-plane Gauss point. The element is deleted only when all Gauss points reach P_thickfail criterion.
- P_thickfail defined in the property and in the failure model(s) (/FAIL) must use the same sign. Otherwise, the P_thickfail defined in the property takes the same sign as the value defined in the failure criterion card /FAIL.
- P_thickfail rules are not used with failure models defined inside the material laws. It is used only for the failure model defined with /FAIL.
- By default, P_thickfail = 1.0 in the property.
- P_thickfail defined in
both the property and in the failure model(s) (/FAIL)
are considered to trigger the element failure.
- Ipos: Shell position or thickness offset:
- Ipos=0: No shell offset
- Ipos=3: The upper surface is coincident with the
element mid-surface.
- Ipos=4: The lower surface is coincident with the
element mid-surface.
- Ipos=0: No shell offset