Identification of Damage for a Single and Double Edge Cracks in a Laminated Composite Beam by Using Harmonic Analysis

摘要

Composite structures are used in many critical engineering applications. In the recent times the research has been increased to identify the damage through the vibrational characteristics of the structure. There have been many theoretical and analytical studies on detection of damage involving analysis of the measured modal parameters, mainly the frequencies. The main objective of this paper is to use coupled response techniques for detecting damages in laminated composite cantilever beams with edge cracks using theoretical harmonic analysis. One method to observe the coupled modes is through the emergence of extra new peaks on a frequency response function plot that can be obtained by using standard vibration testing tools. An attempt has been made to develop a methodology by using coupled response measurements and this will happen to appear only when the structural member contains damage. Therefore, the coupled response can be used to monitor and it can be used to determine the damage existence. The frequency response plots are the only possible method to observe coupled response. The new resonance peaks are correlated to the coupled modes and the appearance of these peaks is the damage identification. The finite element analysis software application package ANSYS 12.0 has been used to obtain the new resonance peaks by using harmonic analysis of undamaged and damaged structures to enable comparisons that throw light on the presence of damages in the structure.