A New Identifying Strategy for 6-DOF Dynamic Interface Force Based on Strain Monitoring

Abstract

Structural tests are to gain confidence in the analytical predictions that support spacecraft development, and ultimately to support the qualification and flight acceptance of the spacecraft system. Based on envelopes of real-time launch vehicle data or simulation results, the input level of the vibration test is calculated with a certain safety margin. This conventional approach to vibration test may lead to over-testing problems, which will severely harm the spacecraft at resonance frequencies. To elaborate on the appropriate force input, Multiple DOF dynamic interface forces during the lift-off must be measured. The force sensor, which should be placed between the spacecraft and launch vehicle, is apparently not a good strategy, because it changes the connecting stiffness and strength of the interface between spacecraft and launch vehicle. Accordingly, a novel identification method for dynamic interaction force, based on the strain status of the spacecraft adapter ring, is proposed in the current study. Some special observation locations are selected along the surface of the adapter ring, on which strain rosettes are pasted to measure the local normal and shear strain. During the lift-off, the telemetry strain signal will be gathered to estimate Multiple DOF forces by theoretical analysis combined with ground test results. It is a promising method for future application.