The following options are available for the source, target, and result file formats:

There are three available methods for performing mesh transformation:

The 4PCS method must 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.

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:

In addition to the transformation options, there are options to convert the unit systems:

The Envyo application implements an equation parser based on the Shunting yard algorithm and is available as MIT license [6]. This equation parser is modified to work with common variables in the LS-DYNA application such as histories, eff. plast. strains, and stresses. Variables are declared, using the & symbol and commands are executed in the order of input. The following variables are available:

The following example illustrates the usage of the equation parser in combination with the lookup tables. The commands following the additional history and lookup table definition are executed in the order of input.

Example of History Variable Manipulation

 AddEleHISVFile#1 = Results A.dyn 
 AddEleHISVFile#2 = Results B.dyn 
 LookupTable#1 = data A.txt,&COL#1,&COL#2,&COL#3 
 LookupTable#2 = data B.txt,&COL#1,&COL#2,&COL#3 
 &HISV#3 = &ADDELE HISV#2 
 &HISV#2 = &ADDELE HISV#1 
 &HISV#4 = abs(&HISV#3-&HISV#2)*0.000467354 
 &EPS = &LookupTable#1,linearInterpolation,&HISV#4,&ELELENGTH,&COL#3 
 &HISV#6 = &LookupTable#2,nextNeighbour,&EPS,&ELELENGTH,&COL#3 
 &HISV#8 = &HISV#2 
 &HISV#9 = &ELELENGTH MAX_NUM_HISV = 8 

Two additional element history files are loaded into the Envyo application, and are stored internally. Additionally, two lookup table files are read. Columns one, two, and three are considered for both files. The column numbers can be different, and the lookup tables may have more than three columns. After reading the data, the following commands are executed:

Part clustering is available on arbitrary history variables or even stress values. The input is as follows:

CLUSTERID#i = STRING, STRING, DOUBLE, DOUBLE, INT (,INT)

Example

CLUSTERID#500004 = &HISV3,MinMax,1.248,9.120E+02,12,6

Target part ID 500004 is split based on history variable #3. The MinMax option is chosen, therefore, internally, the Envyo application creates 6 equally spaced regions between 1.248 and 9.12E+02. Averaged values of history variable #3 are assigned part IDs starting at part ID 12.

CLUSTERID#500004 = &HISV3,AVG,1.248,2.803E+02,12 
CLUSTERID#500004 = &HISV3,AVG,2.803E+02,4.067E+02,13 
CLUSTERID#500004 = &HISV3,AVG,4.067E+02,5.330E+02,14 
CLUSTERID#500004 = &HISV3,AVG,5.330E+02,6.593E+02,15 
CLUSTERID#500004 = &HISV3,AVG,6.593E+02,8.857E+02,16 
CLUSTERID#500004 = &HISV3,AVG,8.857E+02,9.120E+02,17

Target part ID 500004 is split based on the average values on each element of history varibale #3. Averaged values within a range of 1.248 ≤ x < 2.803E+02 are assigned the new part ID 12, values within the range of 2.803E + 02 ≤ x < 4.067E + 02 are assigned the new part ID 13, and so forth.

If the SOLID-SOLID mapping is concerned with degree of cure (DoC) data, it can be augmented by a specific workflow with an explicit focus on the *MAT_TAUGHENED_ADHESIVE_POLYMER material model (also known as *MAT252 or *MAT TAPO). For brevity, the name *MAT252 is used.

For a better understanding of this workflow, some materials in the LS-DYNA application support a history variable for the DoC, which expresses the solidification state of the material during the hardening or curing processes. Depending on the DoC-value (in the range from 0 to 1), the original material properties are altered during the simulation in the LS-DYNA application. One option supporting this workflow is the *MAT307 card, which directly accepts DoC parameters on the history variables in the *INITIAL_STRESS_SOLID cards. On the contrary, it requires several parameters to setup the model. Another option is the *MAT252 card, which represents a more lightweight material model. However, it does not directly support DoC-values on the integration points. Via the two workflows characterized in Output: Initial Stress Cards and Output: New *PART and *MAT252 Cards, even the *MAT252 model can be adjusted based on the DoC parameter.

The main idea is discussed in the next section, while the corresponding commands are presented later in Commands. For a similar workflow, see Theseus to Solid.

While the *MAT252 card does not support DoC-values on the history variables, it does support writing out four other history variables. If these are computed properly based on the DoC-values, they achieve the desired scaling of the material properties in the LS-DYNA application. The overall procedure is described below, while the corresponding commands are given in Output: Initial Stress Cards.

The following table contains the visualization of the curves given in their equations, using these parameters: , , , , , and .

(4–1)
(4–2)
(4–3)
(4–4)

For considering the DoC for the *MAT252 model, another option is to scale the material parameters directly within the Envyo application. As a result, a series of material cards is created and written out to the Envyo application's output file. In order to avoid writing out a modified material card for every element, in this approach, a clustering of elements is conducted, where each cluster represents a unique part with its own material. Otherwise, the strategy is almost equivalent to the one discussed in Output: Initial Stress Cards with the difference that here, each element has its own material definition instead of each integration point. The overall procedure is described below, and see Output: New *PART and *MAT252 Cards for the corresponding commands:

The *MAT252 material model represents an adhesive material and as such, it is typically augmented by the *MAT_ADD_COHESIVE keyword. Since depending on the number of requested buckets, a large amount of new parts and material cards are created, and adding the *MAT_ADD_COHESIVE cards by hand can potentially be a tedious task. Thus, these cards are also generated by the Envyo application based on certain inputs.

The previous section describes workflows that apply to the case, where instead of mapping the results from a source to a target mesh, only the data on a source mesh is modified. No actual mapping takes place. If the discussed workflows are used while transferring data from one mesh to another, the notions from Output: Initial Stress Cards and Output: New *PART and *MAT252 Cards are modified as follows: In both cases, after performing step 1, the DoC-data stored on the integration points is mapped from the source mesh to the target mesh. After that, the procedure continues from step 2 for the target mesh, and the Envyo application's input file must contain the appropriate commands regarding the mapping.

Below is a review of the commands regarding the *MAT252 keyword. First, the commands are covered which are the same for both workflows. Then, in Output: Initial Stress Cards and Output: New *PART and *MAT252 Cards, the additional commands are discussed which are specific to the workflows of Output: Initial Stress Cards and Output: New *PART and *MAT252 Cards, respectively.

TargetMaterialModel = INT	This must be set to 252.
MAT252Parameter = DOUBLE, DOUBLE, DOUBLE, DOUBLE, DOUBLE, DOUBLE	This command is used to inform the Envyo application about the six parameters that are necessary for computing the four functions given in Output: Initial Stress Cards section. The six parameters must be given in the following order: , , , , , and .
MAT252Strategy = INT	1 - Output: Initial Stress Cards is triggered. 2 - Output: New *PART and *MAT252 Cards is triggered.
MAT252Definition = FILE	This command expects a .k- or .key-file containing a single instance of a *MAT252 keyword. The parsed keyword tells the Envyo application what material parameters to work with in this workflow.
DegreeOfCureHistoryPosition = INT	This command is used for telling the Envyo application at which history position is the DoC stored in the source mesh.