Nonlinear Behavior Study of a Nonlinear Supported Simplified Coupled Beam Subjected to Twin Excitations

With the trend toward modern long-span, lightweight, high-strength engineering structures, beam vibration has become increasingly prominent. The existing literature mainly discussed the impact of nonlinear supporting devices on the lateral behavior of beams subjected to single-source excitation. In engineering, multiple-source excitations are common. The lack of related references limits the engineering application of nonlinear supporting devices. Motivated by the above limitations, this work establishes the model of a nonlinear supported simplified coupled beam (NSSCB) subjected to twin excitations. According to the numerical analysis, the presence of nonlinear supports primarily affects the lateral behavior of the NSSCB in three ways. First, peak jumps occur in the lateral behavior of NSSCB. Second, the lateral behavior of NSSCB no longer presents a symmetrical distribution within the sweep frequency range. Third, introducing nonlinear supports reduces the displacement peak at the lateral behavior resonance zones of NSSCB. The peaks in the lateral behavior of NSSCB across different resonant regions occur at specific initial phase skews that vary with nonlinear stiffness. Overall, introducing nonlinear supports effectively suppresses the adverse vibrations of NSSCB at different initial phase skews.