Abstract: Structural strength assessment is pivotal to the development and operation of spacecraft structures. It is currently undergoing a paradigm shift from offline static validation to online dynamic Digital Twin (DT)-based evaluation. Conventional structural strength assessment methods, constrained by idealized modeling assumptions and sparse sensing data, struggle to achieve full-field, real-time, high-precision assessment and evolution prediction of the true state of spacecraft structures. DT technology addresses these limitations by establishing a bidirectional, dynamic mapping between physical entities and virtual models. By fusing multi-source data, multi-fidelity models, and physics-based constraints, DT provides a novel solution path for full-field perception and performance prediction of spacecraft structural strength. This paper focuses on the DT modeling and application for spacecraft structural strength, adopting the research idea of data as the foundation, models as the core, and physical mechanisms as constraints. It systematically reviews the state-of-the-art advances in five key technologies: simulation, sensing, fusion, evaluation, and inversion. Furthermore, the engineering application is discussed in combination with three typical scenarios: ground testing, in-orbit service, and on-orbit construction. Finally, future development trends of DT technology for spacecraft structural strength are prospected.

Key words: Digital Twin, Spacecraft structures, Structural strength, Multi-source data fusion, Performance prediction