This option enables transferring simulation result data from Ansys Fluent software to LS-DYNA application solid element nodes. The result data must be provided as an ASCII based result file which holds integration or result point position and a resulting temperature.
This section covers:
| SourceFile = STRING | Define the name and, if needed, the path of the source file (in this case, a *.txt file holding temperature result data). |
| NumSourceFile = INT | Number of source *.txt files used for the input. This works in combination with ANSYS Fluent software temperature result files and temperature mapping. Temperature data from several files are mapped onto the target mesh as LS-DYNA application lsda tprint - binary files. |
| SourceFile#i = STRING,DOUBLE | If multiple source files are used, first provide the file name followed by a time value used as abscissa value of a temperature-time curve. The output is a LS-DYNA application lsda tprint - file. |
| TargetFile = STRING | Define the name and, if needed, the path of the target file. This must be an LS-DYNA application mesh. |
| MappingResult = STRING | Define the result file name. The mapping result is written into this newly generated file. |
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SourceFileFormat = FLUENTASCII | Define the format of the file that is read. |
For ANSYS Fluent software, result *.txt file holds a description of the data in the first line. The following information includes cell numbers (or IDs), coordinates of the mid-points of the cells and the temperature value.
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ResultFileFormat =LS − DYNA LSDA | Define the result file format. LS-DYNA is the default value. In addition, the output of lsda binary tprint files can be activated. Those can be used within the LS-DYNA application in combination with the keyword *LOAD_THERMAL_BINOUT. |
| TransformedMeshFile = STRING | Specify the file name where the transformed mesh is written. This option is intended solely for postprocessing of the transformation. For additional details, refer to the Transformation Options section below. |
Transformation refers to the transformation of the source meshes. Operations include transformation, rotation, and scaling and they are performed in this order.
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TRANSFORMATION = YES NO | Turn transformation on or off. |
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WriteTransformedMesh = YES NO |
Activates the output of the transformed mesh file to control the accuracy of the applied transformation. Define a TransformedMeshFile, as explained above. |
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RotateSRC =DOUBLE;X DOUBLE;Y DOUBLE;Z DOUBLE; DOUBLE DOUBLE DOUBLE | The source mesh is rotated at an angle (first value) in degrees about the defined axis. Predefined axes are X, Y, and Z. A user-defined axis is also possible, separating three double values with space, following the 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 about the origin using the defined scale factor. |
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ChangeUnitSystem = YES NO | Enables changing the unit system of the source mesh to the unit system of the target mesh. Check the results carefully since not all options may work properly yet. |
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SourceUnitSystem =kg − m − s ton − mm − s kg − mm − ms g − mm − ms | Available unit systems for the source mesh. |
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TargetUnitSystem =kg − m − s ton − mm − s kg − mm − ms g − mm − ms |
Available unit systems for the target mesh. |
| NumTargetPIDs = INT | Define the number of parts in the target mesh which are considered within the mapping. This option must be followed by TargetPID#i definitions. |
| TargetPID#i = INT | Define as many part IDs as given in NumTargetPIDs. 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.
| ALGORITHM =ClosestPoint | The ClosestPoint option accounts for most of the mapping purposes being targeted with the Envyo application. Beginning from the target mesh, the next element or integration point is identified and its data is transferred onto the target mesh. |
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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 radius. The default value is 1.0. |
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MapTemperature = YES NO | Enable this option to ensure that temperatures are transferred. It activates the output of a binary tprint file to be included in the LS-DYNA application analysis using *LOAD_THERMAL_BINOUT. |
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HISV_HANDLING =YES NO CLEAR | Enables you to move and modify history variables in a user-defined way. Regarding the meaning of histories, refer to [20], [4]. If CLEAR, all history variables are removed before generating the result file. If YES, define as many history variables as should be modified. See Equation Parser. |
| MAX_NUM_HISV = INT | Define a new maximum number of history variables. This is an easy way to get rid of unwanted histories which are of no use for the new model, but also enbles extending the amount of histories being output. If a history variable is being moved to a position which is higher then the actual number of history variables in the input deck, the number of histories is extended automatically. |
| SORT = BUCKET | Always use bucket sort for a significant speed up of 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. |
The Envyo application implements an equation parser based on the Shunting yard algorithm and is available as a MIT license [6]. This equation parser has been modified to work with common LS-DYNA application variables such as histories, eff. plast. strains, stresses, temperatures, etc. Variables are declared, using the & symbol and commands are executed in the order of input. The following variables are available:
| &HISV#i |
History variable at position i. |
| &EPS |
Effective plastic strain (the last entry in *INITIAL_STRESS_SHELL which may have a different meaning than eff. plast. strain). |
| &ELELENGTH |
Element length of the current element. |
| &SIG_IJ |
Components of the second order stress tensor. |
| &SIG_INIT | Enables initializing a specific stress value that refers to all stress components. |
| &T | Enables modifying temperature initial values or curves stored on nodes. |
| &ADD ELE HISV#i | Element history variable from file i is used. |
| &LookupTable#1 | Lookup table from file i is used. |
| exp | Exponent. An alternative input is e**. |
| &HISV#i | History variable at position i. |
| &EPS | Effective plastic strain (the last entry in *INITIAL_STRESS_SHELL which may have a different meaning than eff. plast. strain). |
| &ELELENGTH | Element length of the current element. |
| &SIG_IJ | Components of the second order stress tensor. |
| &SIG_INIT | Enables initializing a specific stress value that refers to all stress components. |
| exp | Exponent. An alternative input is e**. |
Example
The following example illustrates the usage of the equation parser. The commands following the additional history are executed in the order of input:
&HISV#4 = abs(&HISV#3-&HISV#2)*0.000467354 &HISV#8 = &HISV#2 &HISV#9 = &ELELENGTH MAX_NUM_HISV = 8
The value of history variable #4 is calculated using the absolute value of history #3 - #2, times a scale factor. Following these operations, history variable #8 is assigned the value at history variable #2, and the element length will be stored at history variable #9. Nevertheless, only eight history variables are written to the final result file due to MAX_NUM_HISV.
The temperature stored on nodes as fixed initial values and/or curves as tempertature over time are transferred from Celsius degrees to Kelvin degrees.