With the widespread use of composite materials and the increasing demand for weight reduction in modern aircraft, the stiffness of the fuselage has gradually decreased, leading to more frequent occurrences of pendulum motions. Traditionally, pendulum test rigs often overlook the elasticity of the fuselage, which can affect the accuracy of the pendulum test results. This study, based on fuselage dynamic characteristic simulation, simulation criteria, and two-degree-of-freedom vibration theory, de