Damage Identification Study Of Reinforced Concrete Beams Based On Non-linear Vibration Characteristics

For the reason of material nonlinearity and geometrical nonlinearity, most of structural vibration systems are non-linear in practice, such as the time variation of frequency. Reinforced conctete beams are important structure components of civil engineering and display obvious non-linear characteristics during vibration just for the material itself being in possess of obvious non-linearity. Besides, there is more or less non-linear vibration after the occurrence of cracks. Once cracks appeared on structure, there will be more obvious non-linear vibration due to the effect of breathing crack.In this paper, introduce the research status of the damage identification at first, the non-linear vibration of reinforced concrete beams and the signal time-frequency analysis methods; Secondly, to analysis the vibration signals result from the reinforced concrete (RC) beams static loading experiment and prestressed reinforced concrete (PRC) beams fatigue loading experiment by the method of time-frequency analysis—Hilbert transform. After getting the curve of amplitude and frequency about different status, compare them and get some viewpoints:transient frequency will increase with vibration amplitude decreasing; the crack affects profound the non-linear vibration characteristics of reinforced concrete beam; it is more available for damage identification by comparing the frequency- amplitude curve than the natural frequency and so on。By the analysis of this article, the damage identification of reinforced concrete beams based on non-linear vbration characteristics is feasible. Because the damage identification based the modal identification will be affected by much bad factors, so it is a better choice to combine the modal identification and the non-linear vbration characteristics for the damage identification.