Mystran Analysis Interface Module (AIM)
Mystran Analysis Interface Module (AIM)
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This is a walkthrough for using MYSTRAN AIM to analyze a three-dimensional wing with internal ribs and spars.
It is presumed that ESP and CAPS have been already installed, as well as MYSTRAN.
Two scripts are used for this illustration:
In our example *.csm file setting up the CAPS fidelity is the first step. If multiple bodies exist in the *.csm file the tag, capsIntent, can be used to distinguish what type of analysis the body may be used for. In this example, the geometry model generated can be used for structural analysis, as shown:
A typical geometry model can be created and interactively modified using design parameters. These design parameters are either design- or geometry- based. In this example, a wing configuration is created using following design parameters.
After our design parameters are defined they are used to setup other local variables (analytically) for the outer model line (OML).
In a similar manner, local variables are defined for the ribs and spars.
Once all design and local variables are defined, a full span, solid model is created by "ruling" together NACA series airfoils (following a series of scales, rotations, and translations).
Once complete, the wing is stored for later use under the name OML.
Next, the inner layout of the ribs and spars are created using the waffle udprim.
An attribute is then placed on ribs and spars so that the geometry components may be reference by the MYSTRAN AIM.
Following a series of rotations and translations the ribs and spars are stored for later use.
Next, the layout of the ribs and spars are intersected the outer mold line of wing, which results in only keeping the part of layout that is inside the OML.
Finally, select faces (airfoil sections at the root) are tagged, so that a constraint may be applied later.
The above *.csm file results in the follow geometry model:
The first step in the pyCAPS script is to import the required modules. For this example the following modules are used,
In order to create a new capsProblem the pyCAPS module also needs to be imported; on Linux and OSX this is the pyCAPS.so file, while on Windows it is the pyCAPS.pyd file. For convenience, it is recommended that the path to this file is added to the environmental variable PYTHONPATH.
Similarly, local variables used throughout the script may be defined.
Once the required modules have been loaded, a capsProblem can be instantiated.
Next, using the loadCAPS() function, the desired geometry file is then loaded into the problem.
After the geometry is loaded, the MYSTRAN AIM needs to be instantiated. Note that below, the capsIntent is set to "ALL" as opposed to "STRUCTURE" as specified above in the *.csm file. This is only valid since there is only one body in the *.csm file. If more than one body existed in the *.csm file the capsIntent during the loadAIM() function call should be set "STRUCTURE".
Once loaded analysis parameters specific to MYSTRAN need to be set (see AIM Inputs). These parameters are automatically converted into MYSTRAN specific format and transferred into the MYSTRAN configuration file. One will note in the following snippet the instance of the AIM is referenced in two different manners: 1. Using the returned object from load call and 2. Using the "altName" name reference in the analysis dictionary. While syntactically different, these two forms are essentially identical.
Along the same lines of setting the input values above the "Analysis" (see FEA Analysis), "Material" (see FEA Material), "Property" (see FEA Property), and "Constraint" (see FEA Constraint) tuples are used to set more complex information. The user is encouraged to read the additional documentation on these inputs for further explanations. Once provided this information is converted into MYSTRAN specific syntax and set in the MYSTRAN configuration file.
After all desired options are set aimPreAnalysis needs to be executed. Based on the input provided, MYSTRAN specific files are generated during this call.
At this point the required files necessary run MYSTRAN should have be created and placed in the specified analysis working directory. Next MYSTRAN needs to executed. In this example an OS system is made such as,
After MYSTRAN is finished running aimPostAnalysis needs to be executed.
Finally, available AIM outputs (see AIM Outputs) may be retrieved, for example:
results in,
When finally finished with the script, the open CAPS problem should be closed.
Issuing the following command executes the script: