Hypervelocity Impact Induced Disturbances on Composite Sandwich Panel Spacecraft Structures.

Disturbances induced by the impact of micrometeoroid and space debris (M/SD) particles at hypervelocity threaten to degrade the stability of satellite platforms below those required for the next generation of European scientific missions. In this thesis, an experimental and numerical study has been performed to characterise and assess the generation and transmission of these disturbances through composite sandwich panel structures with CFRP facesheets and aluminium honeycomb cores (CFRP/Al HC SP) over a wide range of possible in-orbit conditions. An empirical ballistic limit equation (BLE) capable of defining the conditions of structural penetration for CFRP/Al HC SP structures has been developed and applied to predict impact conditions required to induce the range of excitation modes relevant to sandwich panel configurations. Experimentally validated numerical Hydrocode simulations have been performed to evaluate the propagation of disturbance signals in a representative CFRP/AL HC SP platform and define local elastic excitation equivalent to that induced by the impact of a M/SD particle at hypervelocity. The equivalent excitation load is applicable in Finite Element (FE) satellite models for the propagation of impact-induced disturbances throughout a complete satellite body, enabling the assessment of stability degradation at critical regions (i. e. measurement devices).