Experimental investigation of crack detection in cantilever beam using vibration analysis

Abstract

It is very essential that a structure must be run without defects because existence of a defect affects the service life of the structure in harmful way. So, it is important to understand the dynamic behaviour of the structure. Crack changes dynamic performance of the structure and observing this change, the crack depth size and position of crack can be predicted. Non-destructive testing (NDT) methods are used for recognition of crack which are very expensive and time consuming. Current research has studies on modal parameters like natural frequency, damping and mode shape. In this paper, cantilever beam having line crack with changing depth and changing crack position is compared with non-defective beam. For this purpose, the vibrations due of impact ball were studied. The vibration signals from defect-free and line crack beam were equated in the frequency domain with the help of Fast Fourier Transform in Lab-View. In FFT first three natural frequencies were taken to spot the crack depth size and crack location of the beam.