Development, analysis, test and validation of a shock response spectrum (SRS) test bench for space equipment

Kurzfassung

Spacecraft systems and sub/systems are subject to high mechanical energy at a high frequency during shock events. These sudden mechanical loads have been known to cause damage, leading to complete or partial loss of space missions. To prevent this, it is important to validate space equipment for compatibility through Shock Response Spectrum (SRS) testing. The main objective of this master thesis is to understand the behavior of shock loads and to measure SRS for mid-field applications of spaceflight components. The requirements for a new metal-to-metal impact shock test facility have been defined based on extensive research into the shock phenomenon and a thorough examination of existing shock test facilities. To achieve this goal, an iterative approach is employed, where the results and insights gained from each iteration serve as the foundation for developing the subsequent iteration. This method is applied to address the objectives in an attempt to solve the defined problem. In the first iteration, a fundamental model was established to provide a foundational understanding of the set-up and instrumentation. This allowed for the detection of accelerations resulting from the impact and the plotting of SRS for mid-field shock levels within the frequency range of 10 Hz to 10 000 Hz. ANSYS was employed to predict and analyze various parameters such as impact height, impactor mass, impactor material, anvil plate material and mechanical filters that influence the SRS. The generated plots provided insights into how the initial slope (in the low-frequency range of 10 Hz to 1000 Hz), knee frequency and plateau (in the high-frequency range of 1000 Hz to 10 000 Hz) change as the properties and values of these parameters were varied. The second iteration built upon the initial model, further developed the test set-up and conducted a characteristic test campaign. This was based on the knowledge gained from both Finite Element Method (FEM) analysis and the first iteration. The obtained results were compared with the FEM outputs, enhancing the understanding of how different parameters impact the SRS. In the third iteration, the test set-up was refined to meet industry-standard requirements, enabling the testing of flight-grade electro-optical modules against mid-field shock environments found in launch vehicles and spacecraft. This iteration marked the achievement of a highly capable test set-up for conducting shock tests in demanding aerospace applications. The shock test facility has demonstrated its capability to test equipment weighing up to 12 kgrams while maintaining control over the SRS within the frequency range of 100 Hz to 6000 Hz.