Modal analysis, development and modal testing of a nanosatellite structure

Abstract

An evolution is undergoing in the satellite industry towards “SmallSat” development and is becoming a passion for CubeSat developers and educational institutes as an easy and economical access to space. The development of CubeSat structures using 3D printed materials are even more cost-effective and are extending more opportunities for the educational CubeSat research program.

This work describes the fine tuning of Aluminum-ULTEM design of the CubeSat structure, the modal analysis of the structure for the integrity against vibrations during the launch, the development of the satellite vibration model and, the experimentation to verify the modal analysis.

A detailed literature survey is carried out for the selection of design approach, materials, manufacturing and geometry optimization for the modelling of the CubeSat structure. The requirement for static and dynamic load tests in launch environment is discussed. The preliminary design of Aluminum-ULTEM structure is fine-tuned for easy assembly and disassembly of the subsystems stacked inside the CubeSat structure. The finalized design model is needed to be analyzed to verify the structural integrity using finite element analysis (FEA) tool, ABAQUS. The natural frequency, sine vibration and random response spectrum analyses are performed at a given acceleration and PSD values during the launching stage.

The dummy subsystems characterized from the actual subsystems are designed, developed and assembled inside the structure for modal testing while maintaining the center of gravity within the geometric center. The assembled model is then tested to prove the integrity of Aluminum-ULTEM structure for the given vibration loads at the space environment using vibration shaker. The structure parts are examined to find the defects using electronic microscope.

The validation of analyses and tests results confirm that the Aluminum-ULTEM structure has no defects and withholds the integrity of structure during the flight condition. This qualifies the Aluminum-ULTEM CubeSat structure for the launch and flight in the first instance.