An excitation function for hypervelocity impact-induced wave propagation in satellite structures
- Paper number
IAC-06-B6.3.02
- Author
Mr. Shannon Ryan, School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, Australia
- Coauthor
Dr. Frank Schaefer, Fraunhofer-Institut für Kurzzeitdynamik, Ernst-Mach-Institut (EMI), Germany
- Coauthor
Mr. Guy Spencer, Ernst-Mach Institut, Germany
- Coauthor
Dr. Stefan Hiermaier, Fraunhofer-Institut für Kurzzeitdynamik, Ernst-Mach-Institut (EMI), Germany
- Coauthor
Mr. Matthieu Guyot, France
- Coauthor
Mr. Michel Lambert, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2006
- Abstract
There are approximately 11,000 objects larger than 10 cm in diameter currently in orbit about Earth. In addition, tens of millions of sub-centimetre sized items are expected to exist. The threat of these debris particles on the safe operation of spacecraft is becoming increasingly severe. For assessing the risk posed by micrometeoroid and space debris (M/SD) particles on space missions, typically only the probability of structural penetration is determined. Beyond mechanical destruction, the impact of M/SD particles on spacecraft structures induces shock disturbances which are propagated from the local impact point throughout the structural platform. These impacts have long been identified as a source of perturbation for sensitive scientific equipment (e.g. gradiometer, laser interferometer, telescopes), however, the means to quantify these perturbations and thus assess their effect on the successful fulfilment of mission objectives is not available. For future ESA scientific missions (e.g. GOCE, GAIA, LISA), extremely high platform stability is required, orders of magnitude higher than that of past missions, and thus the effect of hypervelocity impact-induced disturbances must be considered in the M/SD risk assessment. In the framework of ESA Contract 18583, M/SD impact-induced disturbances in satellite structures are currently under investigation. In this paper, a function which defines the elastic excitation of a satellite structural wall equivalent to that caused by impact of an M/SD projectile at hypervelocity is derived. The function is a point-source excitation expressed in terms of force as a function of time. Experimentally-validated numerical simulations of hypervelocity impact (HVI) on Aluminium and Carbon Fiber Reinforced Plastic (CFRP) plates performed using a commercial hydrocode are presented, and the methodology for deriving the analytical function from numerical data is described. The excitation function is applied in a number of simulations, and the disturbance propagation is compared to that of an experimental and numerically simulated impact event. The excitation function can be applied in structural FEM codes for global (satellite-wide) propagation of the impact-induced disturbance for quantification of perturbations in structural extremities and therefore assessment of the M/SD risk on the operation of sensitive scientific equipment.
- Abstract document
- Manuscript document
IAC-06-B6.3.02.pdf (🔒 authorized access only).
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