Non-linear dynamic characteristics of a beam with a breathing crack are investigated using finite element method. The article has two main objectives: (1) to assess the crack detection capability of finite element method on a vibrating structure (2) to investigate the effects of crack location, crack depth and excitation frequency on the indications of crack presence. Two dimensional finite element approach is used to model a square cross sectional beam subjected to dynamic loading. Frictionless contact is introduced to avoid any penetration between the crack faces. Time histories and Fourier spectra are obtained for nodal acceleration at specified sensor locations on the beam. On the basis of the results of this research, the capability of finite element method on the crack detection is evidenced by the generation of sub- and higher-harmonics in the Fourier spectra. Both time and frequency domain responses deviate considerably from vibration response of an intact beam. The depth and position of the crack change the amplitude of the harmonics, which can be interpreted as an indicator on the severity of the damage. Furthermore, exciting the beam with frequency of first bending mode of the beam, makes the harmonics more detectable on the frequency domain.
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