关键词: 传递函数, 固有频率, 激励信号, 气动式振动台, 响应信号, 振型

Abstract: Repetitive shock (RS) machines are a kind of significant equipment for reliability enhancement testing. However, many key technologies of RS machines have not been studied in detail in our country. Now a mechanics model of RS machine is established by combining with the vibration theory of elastic rectangular plates. According to the Rayleigh-Ritz method of elastic rectangular plates, the natural frequency and normal vibration mode of the vibration table are calculated, then the transfer function used in dynamic analysis of mechanical system is introduced to the vibration table system, and the force-acceleration transfer function between the location of air hammer and an arbitrary response position on the vibration table is derived. On this basis, a dynamic model of RS machine is constructed, so as to reveal the relationship between the signals of exciting force received by the vibration table and its acceleration response signals. In view of the “ideal” acceleration response signals of the vibration table, the corresponding “ideal” exciting force signals are calculated, and the characteristics of the excitation signals are analyzed, which will provide theoretical guidance for performance improvement and even independent development of RS machines.

Key words: Exciting signal, Mode shape, Natural frequency, Repetitive shock machine, Response signal, Transfer function