Structural Health Determination and Model Refinement for a Deployable Composite Boom

Abstract

The Air Force Research Laboratory Space Vehicles Directorate previously developed a novel composite boom that enables simplified on-orbit deployment for a class of space structures. These composite members are self deploying, reducing the need for hinge and complex motor mechanisms and resulting in decreased weight and structural complexity. Due to its unique capabilities, NASA chose to incorporate this boom architecture into their Nano-Sail D experiment. This composite boom technology was also chosen as the candidate for an investigation into structural health monitoring (SHM) for space structures. Generally, health monitoring has been used on civil and aeroelastic structures for maintenance applications. It is proposed that SHM concepts can be used on space structures to determine health and indirectly predict changes in structural dynamics, which may be crucial for high precision pointing, maneuvering, and life-prediction applications. To begin investigating this topic, a testbed, capable of cyclically damaging the composite booms with a high degree of repeatability, is constructed. As the composite booms are progressively damaged, a series of dynamic interrogations are used to assess the boom. The goal of this research is to correlate SHM features with dynamic properties, leading to an ability to determine a component’s dynamic characteristics purely from SHM data. Using data gathered for SHM testing, the concept of adaptively updating structural models is demonstrated.