Research on high dynamic strain measurement methods for deployable sunshades of star sensors

In the application of star sensors, there is a requirement to further expand the size of the sunshade to improve stray light suppression. However, traditional rigid sunshades are limited by the overall size and size constraints of the fairing, making it impossible to meet the demand. Therefore, deployable sunshades have emerged, which have advantages such as smaller compressed size, larger deployed size, strong ability to suppress stray light, and flexibility. This study focuses on the stress-strain characteristics of a key component of deployable sunshades for star sensors — leaf springs, and proposes a method for high-speed camera measurement of dynamic strain during the sunshade deployment process. First, through a literature review and investigation of relevant application cases, a design scheme using beryllium bronze leaf springs as the driving force for the sunshade was determined. Next, the plasticity parameters of beryllium bronze were obtained through tensile experiments to provide data support for subsequent simulation modeling. Based on experimental data and material parameters, the stressstrain behavior during compression and deployment of the leaf springs was simulated, and their fatigue life was analyzed. The accuracy of the model was verified through experiments, further exploring the relationship between stress-strain and fatigue life of the leaf springs. In conclusion, this study thoroughly investigates the stress-strain characteristics of leaf springs in deployable sunshades for star sensors, evaluates the impact of shocks on leaf springs through the proposed high dynamic strain measurement method, and the results indicate a reasonable design, sufficient margin, and low fatigue probability. This provides theoretical and experimental basis for the design and optimization of deployable sunshades for star sensors.