According to the dynamic characteristics of shipboard helicopter landing, the time-domain load of ship movement on the fuselage under complex sea conditions, the nonlinear dynamic characteristics of rotor damper, and the influence of rotor blade flapping movement and aerodynamic force are considered. The fuselage, rotor lagging damper, blade flapping and lagging movement and aerodynamic model are modeled separately as sub-models, and then the subsystems are integrated according to mechanical principles to finally establish the ship resonance analysis model of helicopter. The method for simulation experiment of ship resonance is put forward. The whole process of ship resonance experiment is dynamically demonstrated by digital simulation technology, which simulates the excitation load on the fuselage caused by the rise and fall and rolling movement of the ship. Actually simulates the lifting collective pitch and conducts periodic excitation by disturbing the control stick. Based on the transient response of the time-domain simulation dynamic system under disturbance, the stability of ship resonance is analyzed. The accuracy of the simulation method is verified through project cases, and the simulation experiment analysis techniques for accurately predicting the unstable boundary of ship resonance are mastered, which provides design and analysis means instead of the experiment that cannot be carried out in model development.

The combination resonance of size-dependent microbeams is investigated. Two harmonic forces act on the microbeam, and combination resonance is observed while the excitation frequencies differ from the resonant frequency. Microbeams with two different sources of nonlinearities including three kinds of boundary conditions, clamped-free (nonlinearity comes from large curvature and nonlinear inertial), clamped-clamped, and hinged-hinged (nonlinearity originates from mid-plane stretching-bending coupling), are taken into consideration to have a deep understanding of this phenomenon. A traveling load acting on the microbeam is presented as a special case of combination resonance. The modal discretization technique is applied to discretize the equations of motion, and then the Lindstedt–Poincare method, a perturbation approach, is employed to solve the resultant equations. The conditions for combination resonance are presented, and frequency-response curves and time histories at the resonance point are obtained for microbeams of each boundary condition. Results reveal that different sources of nonlinearities result in different performances of combination resonance. The free vibration part constitutes a large percentage of the final response. Furthermore, the situation of coexistence of combination resonance and superharmonic (or subharmonic) resonance is determined. The special case demonstrates a higher amplitude than the common combination resonance for all the boundary conditions. Parametric studies are then carried out to discuss the effects of the length scale parameter, excitation force as well as its position, and damping on the performance of the microbeam.