Conception of an MBSE Workflow for the Execution of Thermal Analyses of Space Systems

Abstract

In this thesis a workflow was created, allowing to export the thermal model of a space system stored in the model-based systems engineering (MBSE) software Virtual Satellite and transition it into a thermal simulation model to conduct a thermal analysis using the finite element analysis (FEA) software CalculiX. To achieve this, first, a so called "Concept" was created in Virtual Satellite, enabling to store a thermal model inside the system model. In addition, a number of applications were written for Virtual Satellite to export the thermal model data from the system model. Furthermore a Python script was written for the computer aided design (CAD) software FreeCAD, that automatically meshes the geometry and assigns all thermal model data to the finite element mesh. The script then exports the complete thermal model into readable CalculiX input format. Moreover a function to include orbit data obtained using mission analysis tools was created. This orbit data is used to determine the solar radiation, Earth albedo, and Earth infrared radiation intensities over time and apply them as varying boundary conditions to dynamic simulations. For the interpretation of the simulation results, another application was written in Virtual Satellite. This application reads the CalculiX output file and assigns the obtained temperatures to the corresponding components. To check the validity of the workflow, a number of simulations were executed with ANSYS to compare the results to those of the workflow, obtained with CalculiX. The results showed very similar values, indicating that the workflow works as intended.