Damage Identification Of Pipeline Based On Curvature Modal And Optimization Algorithm

Pipelines are widely used in a variety of applications.including chemical industry, electric power, energy, environment, etc. The damage of a pipeline is usually caused by aging, corrosion, vandalism and so on, which leads to structural damage and even security incidents.Therefore, it is essential to carry out damage identification in pipelines to identify damage location and degree. Structural damage identification method based on vibration characteristics had become a hot research topic in recent years.among them, curvature modal is a modal parameter which is more sensitive to structure local characteristics.The study objects of this article are fixed supported pipelines. Finite Element Method is used to do modal analysis to obtain curvature modal of pipeline before and after damage.The damage locations can be detected in axial and circumferential direction by the the obvious curve mutation of curvature modal difference,including the single and multiply damage in different degrees. Simultaneously,damage degree could not be quantified by curvature mode difference directly, it could only be reflected qualitatively.Because quantifying damage degree is deemed to be a parameter identification problem, the optimization method could be used to solve this difficult problem.Taking the first-order norm of curvature modal difference before and after damage as objective function, the degree of the damage location is optimized by three kinds of optimization methods including particle swarm optimization algorithm, artificial fish swarm algorithm and nonlinear programming genetic algorithm.The optimal performance of nonlinear programming genetic algorithm is better than others algorithms which can be used to accurately identify the damage degree of the damage element by comparing the solution time, the stability of solutions and the solving accuracy of the three algorithms.Finally, the feasibility of using curvature modal difference to identify the damage location of pipeline is verified through experiments.