简支钢梁自振频率对预应力敏感性试验研究

摘要

为了研究简支钢梁基频与预应力值之间的关系,基于FFT(Fast Fourier Transformation,即快速傅氏变换)和HHT(Hilbert-Huang Transform,即希尔伯特黄变换)两种分析方法,以预应力简支钢梁为研究对象,通过不同预应力值下钢梁基频试验研究,对比了两种分析方法的适用性.研究结果表明:传统的力学理论不能很好的解释预应力梁基频与预应力值之间的关系,相比于FFT分析方法,HHT方法能够更好的捕捉到梁体的瞬时频率,梁体基频会随着预应力值的增大而呈现增长的趋势,瞬时频率的震荡幅度也会随之增大.%In order to study the relationship between the fundamental frequency of simple steel beam and prestressed value,two analysis methods based on FFT(Fast Fourier Transformation) and HHT (Hilbert-Huang Transform),with prestressed simply-supported steel beam as the research object,by the research on the steel beam under different prestress value base frequency,the applicability of the two analysis methods are compared.The results show that the traditional mechanics theory cannot well explain the relationship between the fundamental frequency and prestress value,compared with FFT analysis method.The HHT method can better capture the instantaneous frequency of the beam body.The fundamental frequency will increase with the increase of prestress value,and the instantaneous frequency of the oscillation amplitude will increase too.