文章采用Harmonic的谱估计方法,研究了系统不同构件之间通过螺钉连接时,预紧力对系统动态特性的影响.在预紧力相同的情况下,不同量级的外界激励,会造成系统表现出不同的频率响应特性,呈现非线性时不变特性;大量级的外界激励会造成系统预紧力"失效",刚度降低,导致系统的固有频率降低,产生频率漂移,在共振处放大倍数降低.%In this paper, the influence of the preload on the dynamic characteristics of a system with screw connections among different components is investigated with the harmonic spectrum estimation method. It is shown that with a preload of the same order of magnitude, the system exhibits different dynamic characteristics or FRFs under excitations of different orders of magnitude, as a non-linear time-invariant system. High level excitation may invalidate the preload, thus lead to reductions of the stiffness, the natural frequency, and the amplification in the resonance region.
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