Detection of fatigue cracks in a beam using a spatio-temporal dynamical system identification method

The identification of fatique creacks in a beam is investigated in this paper. It is shown that due to the influence of the elastic non-linearity of fatigue cracks, the homogeneity, along with the length of the beam of the spatio-temporal dynamics of the vibrating beam is destroyed. By using spatio-temporal dynamical system identification techniques, a new approach is developed to detect this nonhomogeneity. The cracked beam is divided into several spatial regions and a coupled map latticce (CML) model is identified and verified in one of the regions using an orthogonal forward regression (OFR) least-squares algorithm. This CML model is then used to predict the dynamical behavious of the other regions and in this way to detect the nonhomgeneity of the overall system.