Importance of structural damping in the dynamic analysis of compliant deployable structures

Compliant mechanisms such as tape springs are often used on satellites to deploy appendices, e.g. solar panels, antennas, telescopes and solar sails. Their main advantage comes from the fact that their motion results from the elastic deformation of structural components, unlike usual hinges or prismatic joints, the motion of which is dictated by contact surfaces. No actuators or external energy sources are required and the deployment is purely passive, which appears as a decisive feature for the design of low-cost missions with small satellites or cubesats. The mechanical behaviour of a tape spring is intrinsically complex and nonlinear involving buckling, hysteresis and self-locking phenomena. High-fidelity mechanical models are then needed to get a detailed understanding of the deployment process, improve the design and predict the actual behaviour in the space 0-g environment. In the majority of the previous works, dynamic simulations were performed without any physical representation of the structural damping. These simulations could be successfully achieved because of the presence of numerical damping in the transient solver. However, in this case, the dynamic response turns out to be quite sensitive to the amount of numerical dissipation, so that the predictive capabilities of the model are questionable. In this work based on numerical case studies, we show that the dynamic simulation of a tape spring can be made less sensitive to numerical parameters when the structural dissipation is taken into account.