2007 Volume 1 Issue 7 Pages 886-894
In this paper, a method for identification of a crack in a beam is demonstrated by the use of the genetic algorithm (GA) based on changes in natural frequencies. To calculate the natural frequencies of cracked beams, p-FEM code, which is based on a parametric three dimensional finite element, is developed because the accuracy of the forward analysis is important. In the analysis, an edge crack model is considered. To identify the crack location and the depth from frequency measurements, crack parameters of the beam are coded into a fixed-length binary digit string. By using GA, the square sum of residuals between the measured data and the calculated data is minimized in the identification process and thus the crack is identified. To avoid a high calculation cost, a response surface method (RSM) is also adopted in the minimizing process. The combination of GA and RSM have made the identification more effective and robust. The availability of the proposed method is confirmed by the results of numerical simulation.
