Finite Element Analysis of Stresses in the MIST CubeSat due to Dynamic Loads During Launch

Sammanfattning: A finite element model of the CubeSat MIST was created, in order to assess the stresses that occur in the satellite in response to loads during its launch. Due to size limits of thesoftware used, simplifications had to be made to the geometry of the model. The loads assessed were quasi-static accelerations, random vibrations, shock loads, as well as a combined quasi-static acceleration and random vibration case. The study assumed the worst possible loads from a list of different potential launch vehicles for the satellite. Non-linear boundary conditions could not be modelled, and instead different linear boundary condition combinations were assessed. The results showed that the satellite showed positive margins of safety for the quasi-static loads. The lowest natural frequency for the satellite was above 130 Hz. For the random vibration loads, positive margins of safety could be shown if adverse stresses attributed to the boundary conditions inthe worst case were ignored. The model proved too conservative to qualify the satellite for the shock loads. Shock testing is therefore recommended for future work, unless requirements for waiving the shock testing can be met. The random vibration and combined loads analysis showed that the −X shear panel experienced high stresses in the corners of its windows, and the part should be inspected once environmental tests are conducted. The −X shear panel only showed adverse stresses in the most extreme boundary condition case, where its deformation was deemed unrealistic.