In this paper, a method for identifying of a crack in a plate that uses a genetic algorithm (GA) based on changes in natural frequencies is presented. To calculate the natural frequencies of the cracked plates, a FEM (Finite Element Method) program, which is based on the BFM (Bogner, Fox and Schmidt) model, is developed since the accuracy of the forward solver is important. In the analysis, two types of cracks, i.e., internal and edge cracks are considered. To identify the crack location and the depth from frequency measurements, the width and position of the crack in a plate are coded into a fixed-length binary digit string. 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, the response surface method (RSM) is also adopted in the minimizing process. The combination of GA and RSM makes the identification more effective and robust. The applicability of the proposed method is confirmed by the results of numerical simulation.

Crack Identification of Plates Using Genetic Algorithm

An Indexed Bibliography of Genetic Algorithms Theory and Comparisons

/pdf/an-application-of-genetic-algorithms-to-form-finding-1jf937qro9.pdf

An application of genetic algorithms to form finding analysis of spatial structures

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.

/pdf/crack-identification-in-beam-using-genetic-algorithm-and-3kzz3mw5mn.pdf

Crack Identification in Beam Using Genetic Algorithm and Three Dimensional p-FEM

When a crack exists in a structural member, it leads to changes in natural frequencies. Therefore, cracks in structures can be detected by measuring the vibrations in the natural frequencies of appropriate vibration modes. In this paper a crack identification method for plates is presented using both a genetic algorithm (GA) and FEM. The FEM program is developed to calculate the natural frequencies of the cracked plates based on the BFM (Bogner, Fox and Schmidt) plate model since the accuracy of the forward solver is important. In the study, two types of cracks, i.e., internal and edge crack are considered. To identify the crack location and the depth from frequency measurements, the width and the position of the crack in a plate are coded into fixed-length binary digit string. By using GA, the square sum of residuals between the measured data and the dynamic response is minimized in the identification process and thus the crack is identified. To avoid a large number of calculation cost, Response Surface Method (RSM) is also adopted in the minimizing process. The combination of GA and RSM made the identification more effective ad robust. The availability of the proposed method is confirmed by -results of numerical simulation.

https://www.jstage.jst.go.jp/article/kikaia1979/71/710/71_710_1312/_pdf

Crack Identification in Plates Using Genetic Algorithm

The metastrategy to solve discrete optimization problems is proposed and discussed. The proposed solution procedure is based on the genetic algorithm, GA, in which the idea of simulated annealing, SA is introduced effectively. The procedure has a distinctive feature that the number of generations can be reduced by introducing the idea of the variable mutation ratio in GA based on the annealing schedule of temperature is SA. Applicability is examined with the shape of the optimization problem of the truss structure subjected to three kinds of constraints on homologous displacement, the first eigenfrequency and minimum weight.

Keiichi Tomita

Papers

Optimum Design of Truss Structure by Genetic Algorithm with Variable Mutation Ratio.