Abstract: To address the problem that sudden structural damage during full-scale static tests of highly flexible aircraft easily induces system instability and secondary damage, the loading control simulation method for a rigid-flexible coupled system containing actuators is investigated. First, based on the physical and mechanical characteristics of the components, a full-scale rigid-flexible coupled finite element model comprising nonlinear wing elements and a linear fuselage super-element is constructed. This model achieves high-fidelity simulation of key components from buckling to fracture while balancing computational efficiency. Second, an embedded control framework based on ABAQUS user subroutines is developed. Incremental proportional-integral-derivative (PID) control laws and virtual actuator dynamic models are integrated into the implicit solver, which successfully resolves the computational convergence difficulties caused by abrupt structural changes. On this basis, the sudden fracture condition under ultimate loads is reproduced, and the mechanical response characteristics of unloading strategies, such as displacement locking and passive pressure relief, are compared. An actuator coordinated unloading control strategy based on force feedback is then proposed. The research results indicate that non-closed-loop strategies will induce severe secondary damage due to residual internal force retention or impacts. In contrast, the closed-loop force-controlled unloading strategy can self-adapt to the minimum unloading time determined by the dynamic characteristics of the damaged structure. Under the premise of not generating additional plastic damage, this strategy controls the kinetic energy ratio at 1.02 %, successfully achieving a smooth attenuation of the dynamic response and stable attitude recovery of the full aircraft after sudden damage, providing a feasible method for the control design of high-risk full-scale static tests.

Key words: full-scale static test, virtual test, substructure, embedded control, abrupt structure change