Mechanical Model and Optimization Analysis of Multiple Unidirectional Single-Particle Damper

Particle dampers have good performance of vibration control and noise reduction, and they have been widely studied and applied in the field of high-frequency vibration control, such as aviation and mechanical engineering. However, the vibration characteristics of civil engineering structures are usually low frequency and low amplitude, which restricts the performance of particle dampers. A new type of particle damper, namely the multiple unidirectional single-particle damper (MUSPD), is advanced based on the comparative analysis of the construction characteristics, damping performance, and damping mechanism of a single-particle damper and multiparticle damper. Based on the analysis of the damping mechanism of MUSPD and the integral consideration of the stress state of particles, the mechanical model of MUSPD is established, and an efficient numerical calculation method with variable step size is proposed. For harmonic excitation, the relationship between the optimal motion distance of a particle and other parameters is established by theoretical analysis. In addition, the optimization analysis method of MUSPD subjected to ground motions is proposed, and the rationality and accuracy are all verified. The results show that MUSPD has a better damping effect than a classical particle damper. Because the MUSPD belongs to acceleration (force)-related dampers, the energy of the controlled structure will be transferred as long as the particles collide with the controlled structure, and the frequency richness and randomness of the ground motion spectrum enhance the probability of particles colliding with the controlled structure. Moreover, the site effect has no obvious influence on the damping effect of MUSPD, and it is more suitable for middle- and low-rise structures.