/PROP/TYPE14 (SOLID)

Block Format Keyword This property set is used to define the general solid property set.

Format

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
/PROP/TYPE14/prop_ID/unit_ID or /PROP/SOLID/prop_ID/unit_ID
prop_title
Isolid Ismstr   Icpre Itetra10 Inpts Itetra4 Iframe dn
qa qb h λv μv
Δtmin                
Optional line to activate Sol2SPH option 11
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
Ndir sphpart_ID                

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. 1 2
= 0
Use value in /DEF_SOLID.
= 1 Default, if /DEF_SOLID is not defined
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 Gauss 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.
= 16
Quadratic 20-node solid element, full integration, variable number of integration points.
= 17
H8C, 8-node solid element, full integration, fixed 2*2*2 Gauss integration points.
= 18
8-node solid element, co-rotational, full integration, fixed 2*2*2 Gauss integration points, shear locking-free, Icpre and Ismstr defaults are based on material.
= 24
HEPH 8-node solid element, 1 Gauss integration point, co-rotational system formulation, physical hourglass stabilization.

(Integer)

 
Ismstr Small strain formulation flag. 4
= -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 switch to small strain formulation in Radioss Engine (/DT/BRICK/CST).
= 3
Simplified small strain formulation from time=0 (non-objective formulation).
= 4 Default, if /DEF_SOLID not defined
Full geometric nonlinearities (/DT/BRICK/CST has no effect).
=10
Lagrange type total strain.
= 11
Total small strain formulation from t=0.
=12
Lagrange type total strain with possible switch to total small strain formulation in Radioss Engine (/DT/BRICK/CST).

(Integer)

 
Icpre Constant pressure formulation flag. 5
Only valid when Isolid = 14, 17, 18 or 24.
= -1
Automatically define the best value based on element type and material law.
= 0
The formulation used depends on Isolid value. 1
= 1 Default, if Isolid = 17
Constant pressure formulation to prevent volumetric locking. Use with incompressible material where ν = 0.5 .
= 2
Formulation used is a function of plasticity. This allows the correct modeling of the elastic region when the material is compressible and the plastic region when the material becomes incompressible. Only available for elasto-plastic material laws.
= 3 Default, if Isolid=14 or 24
No reduced pressure integration for compressible materials, like foam.

(Integer)

 
Itetra10 10 node tetrahedral element formulation flag. 7
= 0
Use value in /DEF_SOLID.
= 2
Quadratic /TETRA10 formulation with four integration points and the same time step as a /TETRA4 element.
= 1000 Default, if /DEF_SOLID not defined
Quadratic /TETRA10 formulation with four integration points.

(Integer)

 
Inpts Number of integration points. 6

Only valid for Isolid =14, 16

(Integer)

= ijk (Default = 222):

2 < i,j,k < 9 for Isolid =14

2 < i,k < 3, 2 < j < 9 for Isolid =16

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.
 
Itetra4 4 node tetrahedral element formulation flag. 7
= 0
Use value in /DEF_SOLID.
= 1
Quadratic /TETRA4 formulation with six DOF per node and four integration points.
= 3
Linear /TETRA4 with an average nodal pressure formulation.
= 1000 Default, if /DEF_SOLID is not defined
Linear /TETRA4 formulation with one integration point.

(Integer)

 
Iframe Element coordinate system formulation flag. 8
Only valid for 2D quad elements, and brick elements with Isolid ==1, 2, or 17. Isolid= 14 or 24 always use the co-rotational formulation.
= -1
Automatically define the best value based on element type and material law.
= 0
Use value in /DEF_SOLID.
= 1 Default,if /DEF_SOLID is not defined
Non co-rotational formulation.
= 2
Co-rotational formulation is used. Recommended for models with large rotations.

(Integer)

 
dn Numerical damping for stabilization. 9

Only valid for Isolid=24.

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.

Only valid for Isolid= 1, 2.

Default = 0.10 (Real), must be 0.0 < h < 0.15

 
λ v Numerical Navier Stokes viscosity λ v .

Default = 0.0 (Real)

 
μ v Numerical Navier Stokes viscosity μ v .

Default = 0.0 (Real)

 
Δ t min Minimum time step for solid elements.

Only available when using /DT/BRICK/CST or /DT/BRICK/DEL.

Default = 0.0 (Real)

[ s ]
Ndir Number of particle/direction for each solid element. 11
= 1
One particle in each direction.
= 2
Two particles in each direction, for a total of 8 particles.
= 3
Three particles in each direction, for a total of 27 particles.

(Integer)

 
sphpart_ID Part identifier describing the SPH properties for Sol2SPH.

(Integer)

 

Comments

  1. Isolid - Solid elements formulation
    • For most situations, Isolid = 24 (HEPH) hexahedral element is the best compromise between computational cost and quality.
    • Elements formulation Isolid = 1, 2, and 24 are reduced integration elements with 1 Gauss integration point where as Isolid = 14, 17, and 18 are fully-integrated elements.
    • Isolid = 24 (HEPH) solid elements use a physical hourglass formulation that is similar to the hourglass formulation used by Ishell = 24 (QEPH) shell elements. This hourglass formulation gives better results than the viscous hourglass formulation used by Isolid = 1 or 2.
    • Isolid = 18, the Icpre and Ismstr default values depend on the material and use these recommended values:
      Default Material Laws
      Icpre = 2 2, 21, 22, 23, 24, 27, 36, 52, 79, 81, 84
      Icpre = 3 12, 14, 15, 25, 28, 50, 53, 68, and

      If ν 0.49 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaH9oGBcq GHKjYOcaaIWaGaaiOlaiaaisdacaaI5aaaaa@3CB8@ , then 1, 13, 16, 33, 34, 35, 38, 40, 41, 70 and 77

      70, 77
      Icpre = 1 All other laws and

      If ν 0.49 MathType@MTEF@5@5@+= feaagKart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbbG8FasPYRqj0=yi0dXdbba9pGe9xq=JbbG8A8frFve9 Fve9Ff0dmeaabaqaciGacaGaaeqabaWaaeaaeaaakeaacqaH9oGBcq GHLjYScaaIWaGaaiOlaiaaisdacaaI5aaaaa@3CC9@ , then 1, 13, 16, 33, 34, 35, 38, 40, 41, 70, and 77

      Ismstr = 10 38, 42, 62, 69, 82, 88, 92, 94, 95, 100 and 101
      Ismstr = 11 70
      Ismstr = 1 28
      Ismstr = 2 All other laws
  2. 2D Quad elements.
    The following element formulations are supported for 2D analysis when using /QUAD elements
    • Isolid = 2, 17
    • Ismstr= 4
    • Iframe= 1, 2
    • Icpre= 1, 2.
  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
    • For small strain formulations (Ismstr =1, 3, 11) or elements that switch to small strain formulation (Ismstr =2, 12), the strains and stresses calculated in the material laws are engineering strains and stresses. Otherwise, they are true strains (or total strains) and Cauchy stresses.
    • Ismstr = 10, 12 are only compatible with these material laws 1, 38, 42, 62, 69, 82, 88, 92, 94, 100 and 101 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 could be used.
    • Ismstr = 10 and 12 are not compatible with /TETRA4 with Itetra4 = 3.
    • Ismstr = 11 has been developed for Law 70 (foam), it is only compatible with material laws using engineering total strain (for example, Laws 1, 38 and 70). Generally, more stable results can be obtained when Ismstr =1.
    • Ismstr=12 can be used with /DT/BRICK/CST to automatically switch elements with a low time step from Lagrange type total strain to total small total strain (Ismstr = 11). However, there can be a slight discontinuity of stresses during the change in strain formulation.
    • The Radioss Engine option /DT/BRICK/CST only works with solid properties that use Ismstr = 2 or 12.
    • 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 and Formulation Strain Formulation Negative Volume Handling Method
      /BRICK

      Isolid = 1, 2, 14, 17, 18, 24

      /TETRA4, Itetra4 = 1000

      /TETRA10, Itetra10 = 1000

      Full geometric nonlinearities.

      Ismstr = 2, 4

      Switch to small strain using element shape from cycle before negative volume.
      Lagrange type total strain.

      Ismstr = 10, 12

      Lagrange type total strain with element shape at time=0.0.
  5. Icpre - Constant pressure formulation flag
    • Icpre=1 is used to prevent volumetric locking in incompressible or quasi-incompressible material. For this case, the stress tensor is decomposed into a spherical and deviatoric part. Reduced integration is then used for the spherical part so that the pressure remains constant.
    • Icpre=2 is only available for elasto-plastic laws. To prevent volume locking, additional terms with Poisson’s coefficient are added to the strain. When in the material is still elastic and thus compressible, the Poisson’s coefficient terms are small. As the material becomes plastic and thus incompressible, the Poisson’s coefficient terms increase to prevent volume locking. Refer to the Radioss Theory Manual for additional explanation.
  6. Inpts - Number of integration points
    • For Isolid = 14 and 16, the recommended value is Inpts = 222.
  7. Tetra elements
    • The Isolid flag is not used with 4-node (/TETRA4) or 10-node (/TETRA10) tetrahedron elements.
    • 4-node tetrahedron with Itetra4 = 1 and 10-node tetrahedron Itetra10 = 2 are compatible with all small strain formulation Ismstr.
    • 4-node tetrahedron with Itetra4 = 1000 and all 10-node tetrahedron Itetra10 = 2, 1000 are compatible with Ismstr = 10, 11 and 12.
    • 4-nodes tetrahedron are compatible with the ALE formulation only if using Itetra4 = 1000 or 3 with Itetra4 = 3 recommended to reduce shear locking.
  8. Iframe - Element coordinate system formulation flag
    • When co-rotational formulation is used (Iframe = 2), the stress tensor is computed in a co-rotational coordinate system. If large rotations are involved, this formulation is more accurate but does have a higher computational cost. It is recommended in cases of elastic or visco-elastic problems where shear deformation is important.
  9. dn - Numerical damping and h - hourglass viscosity coefficient
    • Numerical damping dn is used in the hourglass stress calculation for Isolid = 24 (HEPH) solid elements. The energy from numerical damping is included in the time history internal energy output.
    • When comparing results between Isolid = 24 and Isolid = 1 or 2 where dn=h, the numerical damping is ( 2 / 3 ) × 10 3 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaada WcgaqaaiaaikdaaeaacaaIZaaaaaGaayjkaiaawMcaaiabgEna0kaa igdacaaIWaWaaWbaaSqabeaacqGHsislcaaIZaaaaaaa@3E72@ times smaller for Isolid = 24 than Isolid =1 or 2.
    • The numerical Navier Stokes viscosity model is available for all material laws. Note that the output viscosity stress is available just for users law and Isolid =1 (In time history output the viscosity stress is added in the stress).
  10. Output for post-processing
    • For post-processing solid element stress, refer to /ANIM/BRICK/TENS for animation and /TH/BRICK for plot files.
    • In plot and animation files, stress tensor is attached to the co-rotational frame.
  11. Solid to SPH properties (Sol2SPH)
    • When using Sol2SPH, solid elements are converted to SPH particles when a solid is deleted due to contact, a material failure criteria, or time step criteria.
    • The number activated of SPH particles depends on parameter Ndir. The particles properties are computed using the sphpart_ID part number.
    • The option Sol2SPH is only compatible with Isolid = 1, 2 or 24, Iframe = 1 or 2.