Modal analysis of the vibrational characteristics of a 12U nanosatellite in various deployers

This paper addresses the numerical investigation of the dynamic stability of a 12U nanosatellite through modal analysis. Considering the unique internal architecture of a 12U nanosatellite and the absence of a unified structural standard, this study transitions from classical analytical limits to high-fidelity numerical solutions in the MSC Nastran/Patran environment using a model consisting of 278,860 nodes and 1,099,608 elements. To develop an accurate mathematical model of the frame made of 7075 aluminum alloy (dimensions 232×245×363 mm), a combined discretization method was employed. To ensure the reliability of the findings, validation was performed in three ways: numerical results were correlated with an analytical cantilever beam formulation, experimental data from a W6U-type satellite (440 Hz), and TUMnanoSAT test data (255 Hz), showing error margins within the acceptable 10% limit. Model verification was carried out in the frequency range up to 2100 Hz in accordance with the NASA GEVS standard. Special attention was given to the influence of boundary conditions simulating the presence of the spacecraft inside the launch container. Two scenarios were considered: a free support condition and fixed support of one of the side faces. The study identifies a critical 203 Hz frequency discrepancy between mixed-mesh and fully solid discretization strategies, establishing the solid-element approach as a necessary conservative lower-bound estimate (278 Hz) for avoiding vibration load underestimation. Results of the equivalent modal mass analysis confirm that the first vibration mode is always horizontal due to the elongated geometry of the structure. The conservative solid-element model predicted a first natural frequency of 278 Hz, which provides a preliminary frequency margin relative to the commonly used 100 Hz launcher requirement. However, this result should be interpreted as a preliminary modal characterization rather than a complete launch qualification assessment. These findings establish a preliminary dynamic characterization of the 12U structure, providing a robust computational basis for subsequent full-scale vibration testing and optical payload placement optimization.