Abstract:  The compressed stacking structure has potential applications in space structures such as space solar power station and large antennas due to its high utilization of fairing space and easy separation and reassembly after entering orbit. The compressed stacking structure has multiple components and complex connection forms, and the modal testing method based on discrete acceleration sensors cannot monitor the full field modal information of the structure, making it difficult to evaluate the modal of locally connected structures. Therefore, a digital twin modal testing method for space compressed stacked structures was studied. Firstly, a high-precision simulation model of the compressed stacking structure was established and modal analysis was conducted to obtain the structural vibration mode; Then, modal tests were conducted using the hammering method and accelerometer data was collected; Finally, the simulation analysis data and experimental sensor data were fused to construct a compressed stacking structure digital twin, achieving real time monitoring of the entire field mode. The accuracy of predicting the vibration mode of the digital twin body reaches 99.7%, and the fundamental frequency error is 2.6%. It takes 2 seconds from sensor data to completing the calculation and cloud map display of the digital twin body. The results validate the high prediction accuracy and efficiency of proposed method, indicating effectiveness in improving the monitoring range of spatial structural modal experiments.

Key words: space structure, compressed stacking structure, modal testing, data fusion, digital twin