Dynamic Testing of an Inflatable Wrap-rib Reflector Antenna

Dynamic testing of an inflatable wrap-rib reflector antenna with carbon fiber reinforced polymer (CFRP) supporting ribs was conducted. The inflatable reflector antenna was made of thin film, and the precision of off-set parabolic reflector was maintained by tension tailored CFRP ribs with a central hub and an outer inflatable torus. The effects of inner gas pressure and gravity on structural natural frequencies, modal shapes, and modal damping ratios were evaluated experimentally, inflatable wrap-rib reflector antenna with cup-up and cup down configurations with 10kPa and 20kPa inner inflation pressures were tested respectively. In ground vibration test based on experimental modal analysis, the whole antenna was fully deployed and hanged with a rope at central hub in lab environment. A series of impulse tests were conducted with high sensitive load cell to record input force, and several mini tri-axial accelerometers were instrumented on inflatable torus and supporting ribs to monitor the global vibration response, the excitation point was reinforced with a lightweight Alumina thin shell to minimize local deformation. Ground modal analysis results could be used as reference for predicting dynamic characteristics of inflatable wrap-rib reflector antenna on orbit.