Small Satellite (DOE)

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In this tutorial, Design of Experiments (DOE) feature of COSSAN-X will be used on the satellite structure. By performing DOE analysis, it is possible to investigate the individual affects of the various parameters on the response of the structure.

Definition of the input model

The input model has been selected in order to investigate the affect of the Young's modulus, density and thickness on the response of the structure. For this purpose, the Young's modulus of the various components of the structure are modeled as random variables, while the density and thickness are modeled using continous and discrete design variables, respectively. The motivation behind this input model is to show the possibility of using various variable types together within DOE analysis.

Summary of the Input Model

Structural Property

Description     Properties     

Young's Modulus (panels)

Random Variable - Normal distribution Mean = 70 GPa, CoV = 0.15
Young's Modulus (cylinder)

Random Variable - Normal distribution

Mean = 70 GPa, CoV = 0.15
Young's Modulus (nozzle)

Random Variable - Normal distribution

Mean = 70 GPa, CoV = 0.15

Density (whole structure)

Continous Design Variable
[2.0 - 3.0]

Thickness (whole structure)

Discrete Design Variable [0.05, 0.10, 0.15, 0.20]



Once the above model is defined, the following input should be obtained within the GUI:


DOEtutorialInput.jpg


Performing the Design of Experiments Analysis

First, the connector for the analysis has to be constructed. In this tutorial NASTRAN will be used as the 3rd party FE solver. The connector should look as below for the current example:


DOE tutorial2.jpg


The identifiers within the injector (NASTRAN input file) should be defined properly in the GUI. Please see below the injector defined according to the described input model:


DOE tutorial1.jpg


The quantity of interest in this analysis is selected as the normal stresses (sigma-X and sigma-Y) and the shear stress (sigma-XY) of the element 10209. The extractor is defined accordingly within the connector in order to extract these quantities from the f06 file of the analysis:


DOE tutorial3.jpg


Once the connector is defined successfully, the physical model is then created based using this connector. The overview of the physical model can be viewed using the Model editor:


DOEtutorialModel.jpg


Now the model is ready to be used for the DOE analysis. Using the DOE wizard of the COSSAN-X, it is possible to choose among the various design types. The input samples for each design is then created according to this selection:


DOEtutorial7.jpg



Results of the Analysis

The DOE analysis is performed in a similar way to the simulation analysis. Upon selecting the design type, COSSAN-X prepares the samples according to the defined input model. Then the input files for the FE solver are prepared for each experiment by injecting the samples to the positions of the corresponding identifiers. Finally, COSSAN-X extracts the selected responses from the results files produced by the FE solver.


Upon completing the execution of the designs, the results can accessed using the analysis menu:


DOEresults.jpg


The outcome of the DOE analysis can be analysed using the advanced visualization capabilities of COSSAN-X. Below are some examples, i.e. Table view and bar chart view, how the results can be interpreted.


Table view summarizing the input and output of the DOE analysis:


DOEtutorial4.jpg


Bar Chart view showing the variation of the sigma-XY stress among the performed designs:


DOEtutorial6.jpg





Analysis performed with this tutorial