System reliability and sensitivity analysis for extendible support structures with multiple assembly failure modes

The extendible support structure (ESS) is the indispensable ingredient of space antennas, and its assembly reliability is of significant importance for the work performance of the latter. Specifically, pointing accuracy of the panels is critical to the electromagnetic performance of the space antenna and angular error of the locking joints directly determines whether the joint can be successfully locked so as to maintain the structural configuration of the ESS. Thus, this paper proposes a novel analytical approach to system reliability and sensitivity analysis for the ESS considering pointing accuracy and angular errors. At first, the failure mechanism of the ESS due to pointing deviation and angular error is comprehensively analyzed. On this basis, system reliability with those multiple failure modes for the ESS is mathematically defined. To solve this problem, the structural error model of the ESS considering manufacturing errors, assembly deviations and part deformations is first established so that the limit-state functions characterizing the pointing deviation and angular errors are accordingly formulated. Then, a novel framework based on expectation propagation is explored for system reliability and sensitivity analysis with multiple failure modes, of which the notable merit is that it is analytical. Based on this novel expectation-propagation-based framework, the systematic assembly reliability of the ESS is conducted in a closed-form manner. Finally, case studies and practical experiments are conducted to validate the effectiveness of the proposed method. The results demonstrate that it can provide an accurate and efficient system reliability and sensitivity analysis for the ESS.