This option enables the transfer of moldflow orientation data for short and long fiber reinforced composites to solid meshes for further structural analysis.
Several options are available to handle short fiber reinforced composite materials with the LS-DYNA application. The Envyo application supports *MAT_ANISOTROPIC_ELASTIC_PLASTIC (*MAT_157) and output of *ELEMENT_SOLID_ORTHO cards for the use of other arbitrary orthotropic material models within the LS-DYNA application. Support for *MAT_4A_MICROMEC (*MAT_215) is also available.
For more information about the handling of short fiber reinforced materials with *MAT_157, see [11], [16], [15], [10].
This section covers:
| SourceFile = STRING |
Define the name and, if needed, the path of the source file. This should be the Moldflow mesh, translated into LS-DYNA application format. |
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SourceFileFormat = LS-DYNA Patran |
The source file format. |
| TargetFile = STRING |
Define the name and, if needed, the path of the target file. This should be an LS-DYNA application mesh. |
| MappingResult = STRING |
Define the result file name. The mapping result will be written to this newly generated file. |
| OrientationFile = STRING |
Only moldflow-xml files containing the fiber orientation tensor are considered. Extensions enable mapping orientations from the main axis of this tensor and its eigenvalues. |
| TransformedMeshFile = STRING | Specify the output filename for the transformed mesh. This option is intended solely for postprocessing of the transformation. For additional details, refer to the Transformation Options section below. |
| NumTargetPids = INT |
Define the number of parts in the target mesh that are considered within the mapping. This option should be followed by TargetPid#i definitions. |
| TargetPid#i = INT | Define as many part IDs as specified in NumTargetPids. These parts are considered for the mapping. |
| NumSourcePIDs = INT |
Define the number of parts in the source mesh that are considered within the mapping. This option should be followed by SourcePID#i definitions. |
| SourcePID#i = INT | Define as many part IDs as specified in NumSourcePIDs. These parts are considered for the mapping. |
Note: The options above specifically narrow down the scope of the mapping procedure to defined-part IDs. Other parts are ignored on both the source and target meshes.
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TRANSFORMATION = YES NO | Enable/disable the transformation option. |
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TransformBack = YES NO | Activate/deactivate backward transformation. |
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WriteTransformedMesh = YES NO | Flag to enable output of the transformed mesh used for mapping. This enables success verification for the transformation. If set to YES, a TransformedMeshFile must be specified (see above). |
There are three available methods for performing mesh transformation:
TRAFO_OPTION is required:
Iterative Closest Point (ICP)
Four-Points-Congruent Sets (4PCS)
TRAFO_OPTION is not required:
User-defined translation and rotation
The 4PCS method should be used with caution, as it is fully automatic and may not accurately transform stress tensors and fiber orientations between different coordinate systems. The ICP algorithm is the recommended approach.
The user-defined translation and rotation options are listed underneath TRAFO_OPTION.
Note: Transformation options are used to transform the source mesh.
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TRAFO_OPTION = 4PCS ICP | Flag that enables specification of the required transformation option. |
| NodalPair#i = INT INT | Define nodal pairs to initialize mesh alignment for the ICP algorithm. You can specify up to ten nodal pairs, with a minimum of three required. In each pair, the first integer represents a node ID in the source mesh, and the second corresponds to a node ID in the target mesh. Input values should be space-delimited, with each nodal pair provided on a separate line. |
| MAX_NUM_ITER = INT | Maximum number of iterations to be performed by the 4PCS algorithm. |
| GLOBAL_ERR = DOUBLE | Global error measurement to accept transformation as best fit for the 4PCS algorithm. |
| MATCHING_POINT_DIST = DOUBLE |
Maximum distance between points such that they are accepted as matching (4PCS). |
| PERCENTAGE_OF_MATCHING_POINTS = DOUBLE | Percentage of matching points for transformation acceptance (4PCS). |
Additionally, a custom sequence of user-defined transformations can be applied. These transformations are executed in the order in which they are specified and multiple transformations may be defined:
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RotateSRC = DOUBLE;X DOUBLE;Y DOUBLE;Z DOUBLE; DOUBLE DOUBLE DOUBLE | The source mesh is rotated by a specified angle (first value, in degrees) around a defined axis. Predefined axes include X, Y, and Z. Alternatively, a custom axis can be specified by providing three space-separated floating-point values following a semicolon (; x y z). |
| MoveSRC = DOUBLE DOUBLE DOUBLE | The source mesh is moved along the user-defined vector (x y z). |
| ScaleSRC = DOUBLE | The source mesh is scaled around the origin using the defined scale factor. |
In addition to the transformation options, you can convert the unit systems:
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ChangeUnitSystem = YES NO | Activate/deactive unit system conversion. |
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SourceUnitSystem = kg - m - s ton - mm - s kg - mm - ms g - mm - ms lb - in - s | If unit system conversion is activated, provide information about the source unit system. |
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TargetUnitSystem = kg - m - s ton - mm - s kg - mm - ms g - mm - ms lb - in - s | If the unit system conversion is activated, provide information about the target unit system. |
| ALGORITHM = ClosestPoint | The only available option is ClosestPoint. Values are mapped to the nearest node, integration point, or element center. |
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Search_Radius = SrcEleLen TarEleLen DOUBLE | Specifies the search radius for the mapping algorithm. By default, SrcEleLen is used, which sets the radius to the average element size of the source mesh. Alternatively, you can use TarEleLen to apply the average element size of the target mesh, or provide a positive DOUBLE value to define a custom radius. |
| Scale_SearchRadius = DOUBLE | Coefficient to scale search buckets in the bucket search algorithm. |
| ETYP = INT | 1 - Reduced integrated solid elements 2 - Fully integrated solid elements This accounts for hexahedral elements as well as tetrahedral elements. ETYP = 1 therefore activates the mapping to reduced integrated tetrahedral elements (LS-DYNA ETYP 10 or 13), whereas ETYP = 2 activates the mapping to fully (4-point) integrated tetrahedral elements (LS-DYNA ETYP 4, 16 or 17). The number of integration points for tetrahedral elements can also be changed with NIPTETS |
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OUTPUT_OPTION = INITIAL STRESS ONLY |
Only *INITIAL_OPTION cards are written to the mapping result file. Nodes and elements are skipped. |
The mapped orientations are given by the main axis of the orientation tensor corresponding to the largest eigenvalue. This enables modeling with any arbitrary orthotropic material law available in the LS-DYNA application.
| MapStress = NO |
Define whether *INITIAL_STRESS_SOLID cards should be written. For the *ELEMENT_SOLID_ORTHO option, set this flag to NO. |
| MapMainDir = YES |
Activate mapping of the main directions to *ELEMENT_SOLID_ORTHO cards. |
| NIPTETS = 1 |
1 - Activates mapping to 1-point tetrahedral elements (LS-DYNA ETYP 10 or 13). 4 - Activates mapping to 4-point tetrahedral elements (LS-DYNA ETYP 4, 16, or 17). 5 - Activates mapping to 5-point tetrahedral elements (LS-DYNA ETYP 4, 16, or 17). For the *ELEMENT_SOLID_ORTHO option, set this option to 1. |
| SOLID_OPTION = ORTHO |
Activates the output of *ELEMENT_SOLID_ORTHO cards. |
| SORT = BUCKET | Using bucket sort is strongly recommended, as it provides a substantial performance improvement for the search algorithm. |
| REPEAT = YES | Enable this option to ensure that all elements and integration points receive mapped data. When there is a significant difference in element sizes between the source and target meshes, the default bucket refinement may be insufficient to cover all points, sometimes by design. In such cases, this flag must be set to guarantee complete data coverage. |
This section describes the options available for the mapping of material properties for *MAT_ANISOTROPIC_ELASTIC_PLASTIC (*MAT_157). The initial input is the same as above, with minor changes to the target options and additional cards specific for the initialization of material properties for (*MAT_157) with the *INITIAL_STRESS_SOLID card. You must choose which history variables should be initialized through the Envyo application.
This section covers:
| TargetMaterialModel = 157 |
Specify the target material model used in the subsequent analysis, if not initializing with *ELEMENT_SHELL_COMPOSITE. Options are 157 or 215 referring to respective material model IDs in the LS-DYNA application’s material model manual [20]. |
| MapStress = YES |
Define whether *INITIAL_STRESS_SOLID cards are written. If data should be made available for the *MAT 215 material model via *INITIAL_STRESS_SOLID cards, this option must be YES. |
| MapMainDir = NO |
Activate mapping of the main directions to *ELEMENT_SOLID_ORTHO cards. For usage with *MAT_215, this option is NO. |
| NIPTETS = INT |
1 - Activates mapping to 1-point tetrahedral elements (LS-DYNA application ETYP 10 or 13). 4 - Activates mapping to 4-point tetrahedral elements (LS-DYNA application ETYP 4, 16, or 17). 5 - Activates mapping to 5-point tetrahedral elements (LS-DYNA application ETYP 4, 16, or 17). |
| IHIS = INT |
Flag that defines the material parameter written to *INITIAL_STRESS_SOLID cards for *MAT_157, according to [20]. The following values are supported: |
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IHIS = 1 - q-values are written to the first six history variables. | |
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IHIS = 3 - q-values are written to the first six history variables, tensor components Cij are written on history variables #7 - #27. | |
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IHIS = 11 - q-values are written to the first six history variables, tensor components Cij are written to history variables #7 - #27, table IDs for strain rate dependent plasticity are defined in history variable #28. | |
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For IHIS = 1, no further input is required. | |
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If IHIS > 1, define the following variables: | |
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HomogenizationMethod = Halpin − Tsai Tandon − Weng Voigt Kukuri Mori − Tanaka_1 Mori − Tanaka_2 Mori − Tanaka_3 | Define the homogenization method used to calculate the unidirectional stiffness matrix. For further information about these methods, see [10] or [16]. |
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ClosureApproximation = Linear Quadratic HybridA HybridB ORF ORS |
Define the closure approximation method used to calculate the 4th-order orientation tensor from the 2nd-order orientation tensor given by Moldflow. For further information about these methods, see [10] or [16]. ORF calls the orthotropic fitted closure approximation proposed by [12], distinguishing between different fiber interaction coefficients based on the equation provided in [7]. ORS refers to the orthotropic smooth closure approximation. |
The following elastic constants must be defined:
| E11F = DOUBLE | Fiber Young’s modulus in main direction. |
| E22F = DOUBLE | Fiber Young’s modulus perpendicular to the main direction. |
| RHOF = DOUBLE |
Fiber density. |
| PRBAF = DOUBLE |
Fiber in-plane Poisson’s ratio. |
| PRCBF = DOUBLE |
Fiber out-of-plane Poisson’s ratio. |
| G12F = DOUBLE |
Fiber shear modulus. |
| EM = DOUBLE |
Matrix Young’s modulus. |
| RHOM = DOUBLE |
Matrix density. |
| PRM = DOUBLE |
Matrix Poisson’s ratio. |
| AspectRatio = DOUBLE |
Fiber aspect ratio (length/thickness). |
| FiberVolumeFraction = DOUBLE |
Fiber volume fraction in percent. |
| InclusionShape =
Ellipsoidal Spherical Needle Disc |
Shape of the inclusions. |
If IHIS > 3, you must define several direction-dependent curve files, representing different strain rates, so that the strain-rate and direction-dependent plasticity can be defined. The following input can be given:
| NumberOfCurveFiles = INT |
Define the number of curve files to be read. |
| CurveFileName#i = STRING |
Define the name and, if needed, path of the curve files. This card must be written NumberOfCurveFiles times. |
| NumberOfDirections = INT | Define the number of directions to which the curve files belong. The recommended value for short fiber reinforced plastic materials should be 3 |
| Direction#i = DOUBLE | Define angles, relative to the direction of flow, used to generate the plasticity curves. Typical angles are 0◦, 45◦, and 90◦. This card must be written NumberOfDirections times. |
| NumberOfStrainRates = INT | Define the number of strain rates to which the curve files belong. |
| StrainRate#i = DOUBLE | Define the strain rates that are considered by the defined curves. This card must be written NumberOfStrainRates times. |
| StrainRate#iDirection#j = INT | Define the curve IDs that belong to the respective strain-rate/direction combination. This card must be written NumberOfDirections x NumberOfStrainRates times. |
This section describes the options available for the mapping of material properties for *MAT 4A MICROMEC (*MAT 215). The initial input is the same as above, with minor changes to the target options and additional cards specific to the initialization of material properties for (*MAT_215) with the *INITIAL_STRESS_SOLID card.
| TargetMaterialModel = 215 | Define the ID of the target material model corresponding to [20]. Here, it must be 215. |
| MapStress = YES | Define whether *INITIAL_STRESS_SOLID cards are written. If data must be made available for the *MAT_215 material model via *INITIAL_STRESS_SOLID cards, this option must be YES. |
| MapMainDir = NO |
Activate mapping of main directions to *ELEMENT_SOLID_ORTHO cards. For usage with *MAT_215, this option is NO. |