The Results Available for Solid Elements
The results available for solid elements
Solid elements write the results to the .PTF file. The following tables show the raw data components, and those derived by D3PLOT.
Symmetric stress tensor: |
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This is written in the global cartesian coordinate system. It is always output, regardless of any of the switchable settings on the *DATABASE_EXTENT_BINARY control card. (See Controllable contents of the complete state file )
The stress components that can be derived by D3PLOT ( Manipulations of Stress Tensor Components ) are:
In addition D3PLOT will calculate the 2D in-plane maximum and minimum principal stresses and maximum shear stress:
These "2D" values are calculated by the following process:
- Rotate the global stress tensor to the element local axis system.
- Using only the local Sxx , Syy and Txy terms calculate the 2D max and min principal stresses
This means that the local Szz, Tyz and Tzx terms are implicitly treated as being zero and the element is treated as being plane stress, which is really a nonsense for a solid element in which a full three-dimensional stress state is achieved. These components are calculated for solid elements to provide consistency with thin and thick shell output, but the resulting values are of limited usefulness - use with care!
Effective plastic strain |
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The effective plastic strain is always output, as above. It has no intrinsic direction. (see A further explanation of strain components for more information about strains).
Extra variables for solidsIf NEIPH has been defined on the *DATABASE_EXTENT_BINARY control card then <neiph> "extra" variables will be written. D3PLOT will accept any number of these, but will only process the first 99. These have the names:
They are treated as separate scalar values of unknown type which may be contoured and written out, but not processed in any way. |
*DEFINE_MATERIAL_HISTORIES for solidsIf *DEFINE_MATERIAL_HISTORIES cards have been defined, these will overrule the value of NEIPH on the *DATABASE_EXTENT_BINARY control card and the number of "extra" variables will be defined by the number of *DEFINE_MATERIAL_HISTORIES cards. D3PLOT will accept any number of these, but will only process the first 99. These have the names: They are treated as separate scalar values of unknown type which may be contoured and written out, but not processed in any way. The *DEFINE_MATERIAL_HISTORIES component category is only available in D3PLOT if a ZTF file is present. These variables will also be present in D3PLOT in the Extra component category as described above. When the NAMES option is active, history variable components are given this name in D3PLOT (the first 27 characters of the name will be displayed), otherwise they are given the corresponding label. |
Directional strain tensor for solidsIf STRFLG has been set on the *DATABASE_EXTENT_BINARY control card the symmetric strain tensor for solids will be written out. This is always oriented in the global cartesian coordinate system. (see A further explanation of strain components for more information about strains) |
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And the strains derived from these by D3PLOT (see Manipulations of Strain Tensor Components ):
The following components are the shear strain components multiplied by a factor of 2. See Manipulations of Strain Tensor Components for more details.
In addition D3PLOT will calculate the 2D in-plane maximum and minimum principal strains and maximum shear strain:
These "2D" values are calculated by the following process:
- Rotate the global strain tensor to the element local axis system.
- Using only the local Exx , Eyy and Exy terms calculate the 2D max and min principal strains
This means that the local Ezz , Eyz and Ezx terms are all implicitly treated as being zero and the element is treated as being plane strain. Since solid elements develop a full 3D stress and strain state these are not really useful data components, and are computed only for consistency with thin and thick shell output - use with care!
D3PLOT will calculate the ratio of E2MIN_2D_PRINC_STRAIN / E2MAX_2D_PRINC_STRAIN which can be used to give an indication of the stress state:
A problem arises when trying to distinguish between biaxial tension and biaxial compression as in both cases they return a +ve value. In fracture predictions it is important to distinguish between the two so, whilst it is possbile that a compressive state could give a shear fracture, the most likely outcome would be buckling. Therefore, when both E2MAX_2D_PRINC_STRAIN and E2MIN_2D_PRINC_STRAIN are negative (or 0) a value of 1.1 is returned to indicate a compressive state.
The ratio is capped to -100 to avoid large values if E2MAX_2D_PRINC_STRAIN is relatively small compared to E2MIN_2D_PRINC_STRAIN
Internal Energy Density for solids
For solid elements, D3PLOT may derive the internal energy density for solids in the elastic regime. This is not computed by default, users wishing to use it should contact Oasys Ltd Support first for advice.
Components derived geometrically by D3PLOT
Strain rate is calculated directly from the translational velocity gradients and nodal displacements, giving an instantaneous result at a given time:
Volume and relative volume ( Vol CURRENT / Vol Original ) are calculated from nodal coordinates:
| RV_RELATIVE_VOLUME | VOLUME |
Geometric components
These components are extracted from the topology, and can be output in :
| MN_MATERIAL_NUMBER | LN_LIST_OF_NODES | FE_FACING_ELEMENTS |