DYNAMIC RESPONSE OF A MULTIPLE CRACKED CANTILEVER BEAM

Ch. Ratnam, G. Nageswara Rao, BSN Murthy, V. Vital Rao

Abstract: Dynamic response information is useful in structural health monitoring to identify the location and magnitude of damage. Estimation of natural frequency of structure is very important for vibration based damage detection and is not usually calculated simply and can sometimes be complicated. In the present approach a cantilever beam is illustrated with aFinite element model (FEM) andalso a general MATLAB program is developed for multiple cracked cantilever beamto obtain eigenvalues and eigenvectors. The results obtained by using FEM through MATLAB computer program are validated with experimental results.Experimentation is conducted on cantilever beam for both damaged and undamaged cases by using Laser Doppler vibrometer (LDV).The recorded signal isanalyzed by signal processing in VibSoft to measure the frequency response. It is observed that the natural frequencies of the system decreases with increase in crack size. The theoretical values are very much close to experimental values. The results are presented in the form of tables and graphs for each case.

Keywords: Dynamic response, Crack, Cantilever beam, FEM, LDV

DOI: https://doi.org/10.15623/ijret.2015.0412038