A NOVEL SEMI-EMPIRICAL TOOL FOR HYPERVELOCITY COLLISION SIMULATIONS

The Collision Simulation Tool developed at the University of Padova aims to predict fragments distributions in case of subcatastrophic and catastrophic impacts by modelling the consequences of orbital impacts involving large debris and satellites. CST makes possible to model a large variety of collision scenarios involving complex systems such as entire satellites with many design details included, providing statistically accurate results with a computational effort orders of magnitude lower than hydrocodes. To this end, the simulation approach is based on a hybrid modelling strategy, in which every colliding object is described as a gross net of Macroscopic Elements (ME) representing spacecraft elementary building blocks. On one hand, individual fragmentation of Macroscopic Elements is addressed through the use of semi-empirical breakup models applied, at element level, only to those spacecraft parts which are involved in the collision. On the other hand, structural distortion, fracture and separation of satellite broken parts are modelled with a discrete-element approach through the simulation of momentum transfer to Macroscopic Elements through the net, taking into account energy dissipation inside elements and across links. This paper provides a description of the CST simulation methodology and framework; simulations of simple targets (simple plates and Whipple Shields) as well as subscale spacecraft models are compared with empirical data from ground-based impact tests.