Anti-creep pretension determination of a mesh reflector antenna for long term surface accuracy retention

Abstract

During the in-orbit service, mesh reflector antennas inevitably withstand the long-term creep behavior, resulting in changes in material properties and loss of cable tensions, thus decreasing the structural stiffness and surface accuracy. Pretension design plays an important role for mesh reflector antennas in achieving high surface accuracy, and different levels of pretension also affect the antenna’s creep behavior in the time dimension, which can be actively utilized to improve stability of the antenna surface accuracy. In this paper, we present an anti-creep pretension determination method for mesh reflector antennas to improve the surface accuracy stability. The creep model in the discretized time domain is adopted to describe the cable creep behavior. The time-related nonlinear equilibrium equation of the mesh reflector antenna is established with the force density method. The time-related tangent stiffness matrix is derived and adopted to solve the nonlinear equilibrium equation by the Newton-Raphson method, providing an effective way to analyze the antenna creep phenomenon in the discretized time domain. Aiming to minimize the long-term peak value of the time-variant surface error, the pretension schemes are generated and optimized. Finally, this approach is effectively applied to a thirty-unit mesh reflector antenna and its feasibility and effectiveness are verified.