Representing uncertainty in space structures through a random block matrix approach

Characterisation of non-deterministic behaviour in the context of built-up reduced order models is addressed in this paper. A new method is proposed, such that uncertainty can be independently controlled in individual matrix partitions of any component mode synthesis (CMS) subsystem. Unlike existing techniques, the separate generation of random off-diagonal matrix partitions is an inherent feature of the approach. Its foundation is a framework enabling the generation and sampling of fixed rank positive semi-definite (PSD) 2×2 random block matrices. The method is validated against a direct Monte Carlo simulation (MCS) for the case of a spacecraft structure under acoustic excitation. Good prediction agreement against the MCS is observed, along with computational time improvements nearing 3 orders of magnitude.