Elastic-plastic optimisation of a cable-rib satellite antenna.

Cable-rib satellite antennas are facing a growing challenging quest of technological operation and connected structural performance, specifically in the context of large-scale, deployable aerospace applications [1]. In the framework of Limit Analysis, as a specific tool of structural modelling, within the Theory of Plasticity, accounting for potential material non-linearity, up to structural collapse, as an assumed general paradigm of structural resilience, the present contribution analyses a specific cable-rib satellite antenna through a novel evolutive algorithm (see [2]-[4]), in order to assess possible activation of plastic joints, under perfect-plasticity conditions, and to consistently estimate displacements at incipient collapse. Modelling both beam elements (with a tubular cross section) and cable elements, the underlying elastic-plastic analysis is then coupled to an optimisation process, toward minimisation of displacements at incipient collapse, with respect to initial cable shortenings or, in an equivalent manner, cable pretensions. Further investigations are also developed, within the optimisation tool, re-joining dynamic analyses together with elastic-plastic analyses, in order to minimise the total mass of the structure, at varying cross-section properties for each structural element, at given material features, under plastic consistency constraints. The adopted evolutive elastic-plastic algorithm, combined with optimisation tools, is proven to be an efficient structural modelling strategy, both from computational and design standpoints, allowing for effective analyses of deployable satellite antennas, even beyond for the characteristic sample under target here.