Taylor, Emma A.; Glanville, Jonathan P.; Clegg, Richard A. and Turner, Robert G.
Hypervelocity impact on spacecraft honeycomb: hydrocode simulation and damage laws.
International Journal of Impact Engineering, 29(1-10),
Spacecraft honeycomb structures provide the primary shielding against meteoroid and debris impact for unmanned spacecraft in orbit around the Earth. Hypervelocity impact velocities for spacecraft in Low Earth Orbit can reach speeds of 15-16 km/s yet, for the particle diameters of interest, experimental test facilities are limited to maximum velocities in the range 7-8 km/s. Previous tests onto aluminium and cadmium facesheets with honeycomb core (or cylindrical equivalent) and composite facesheets with aluminium honeycomb core have identified that the honeycomb core influences the impact process (typically called "channelling"). Tests also identified that the shielding performance was altered under oblique incidence impact. Hydrocode computer simulations can be used to explore the velocity regime beyond the capabilities of existing experimental test facilities. In order to investigate the impact processes on honeycomb and to evaluate damage equation methodologies at velocities beyond the experimental test regime, a simulation programme was defined using the hydrocodes AUTODYN-2D and 3D. First 2D axisymmetric, simulations of normal impact on single and double honeycomb were carried out and compared with published test data. Good agreement was obtained. To model the required geometry, Lagrange, Shell and Smooth Particle Hydrodynamics (SPH) solvers were coupled together. Further 2D simulations were then carried out at velocities of 7, 11 and 14 km/s on two spacecraft honeycomb structures representative of those used in unmanned spacecraft. The ballistic limit was identified and, for impacts above this limit, the post-perforation debris cloud characteristics were calculated by evaluating the momentum recorded on a witness plate or by calculating a momentum pressure function of the post-perforation debris cloud. A honeycomb damage equation, based on the semi-infinite penetration equation, was compared with the simulation results. It shows better agreement with both experimental test results and 2D simulations than the Whipple bumper shield (Christiansen-Cour-Palais) formulation previously applied to honeycomb data, and therefore provides a means to characterise single honeycomb shielding performance as part of spacecraft design and verification activities. The simulation methodology was extended and two 3D oblique incidence simulations were carried out at 11 km/s. These simulation results were also consistent with the equation predictions. (C) 2003 Published by Elsevier Ltd.
||debris; honeycomb; hypervelocity; damage laws; ballistic limit; spacecraft structure; hydrocode; AUTODYN
||Science > Physical Sciences
||25 Jan 2007
||02 Dec 2010 19:56
Actions (login may be required)