Abstract: The operation accuracy of mechanical equipment such as flexible space manipulator, large-scale deployable antenna is significantly affected by the nonlinear vibration at the joints and the large deformations during its movement. This paper, taking the large-deformation beam with bolted joint structure as the research object, carries out experimental researches on its dynamic modeling and vibration characteristics, and verifies them through numerical calculation. An experimental bench with bolted flexible beams was built, and experimental tests of percussion and sinusoidal excitation were carried out. The experimental results show that the modal frequency of the bolted-connected flexible beam is lower than that of the continuous beam (without connection), and the damping is increased, which exhibits the nonlinear modal characteristics that the modal frequency decreases as the excitation energy increases. Changing the bolt connection position will significantly affect the structural modal frequency, and the influence law can be qualitatively reflected by solving the linear matrix eigenvalues.

Key words: bolted joints, large deformation beam, nonlinear normal modal, dynamic response, experiment