Vibration Analysis and Prediction Natural Frequencies of Cracked Timoshenko Beam by Two Optimization Techniques - Cascade ANN and ANFIS

Abstract

The prediction of the location and depth of a crack in beam type structures is an important aspect of structural health monitoring for ensuring their safety. In the present work, two methods are followed to capture the effect of open transverse crack on the fundamental as well as higher order modes of free vibration of an isotropic Timoshenko beam under clamped-clamped boundary condition using Ritz approximation. In the first method, crack beams are modelled with a rotational spring. For the second method, three-dimensional Finite Element Analysis is carried out using solid element. Dynamic characteristics are optimised by two different techniques, namely, Cascade Forward Back Propagation (CFBP) artificial neural network and Adaptive Neuro-Fuzzy Inference Systems (ANFIS). The damage is modelled and then the measured frequencies are compared to the predicted frequencies to determine the damage.