Mass and stiffness identification of particle beam system based on a dynamic effective mass method

We perform an investigation on identification of the complicated particle beam system, focusing on the occurrence and the mechanism of the resonant peaks. The concept concerning dynamic effective mass of the particle beam system is put forward, which realizes the decoupling of mass, stiffness, and damping. Excitation strategies, such as constant amplitude variable frequency sweep, are used during the testing process. The relationships between the dynamic effective mass of the particle beam system and the excitation frequency are recorded to study the mass and stiffness effects of the system. The results show that the variation of system stiffness and the negative mass are the main reasons for occurrence of resonant peaks. On the basis of the variation tendency of stiffness, we infer that the particle flow state transits from solid state to liquid state and thus, the whole frequency band is divided into three regions with an increase in excitation frequency. Within the region of solid state, resonant frequencies can be estimated roughly, which also proves reliability of the inference. The influence of burial depth and force amplitude on stiffness and mass of the system is investigated to reveal the tendency of all peaks and explain the jump phenomenon roughly.