Research on Quantitative Identification of Pipe Crack Based on Vibration

Pipe plays an important role in the petrochemical industry. Developing pipe testing technique can avoid or decrease accidents and is an important guarantee for the safety service of pipe. In this paper, a method is presented to identify crack location and size, which is based on the finite element method (FEM) and model modification. Pipe structure is dispersed into a series of nested thin-walled pipes. By making use of stress intensity factor of the thin-walled pipe, the equivalent stiffness of pipe crack may be calculated. On this basis, the finite element method is used to establish the dynamic model of cracked pipe, and the model is efficiently modified by simulation and experiment. Then a quantitative diagnostic method of crack is constructed by combining forward problem and inverse problem, which provides a non-destructive testing technology with vibration for the pipe structure. The efficiency of the proposed method is verified by experiments.