Study on plastic damage assessment technology of pipeline steel based on nonlinear mixed frequency ultrasound

In the service process of oil and gas pipeline, due to high pressure, large deformation and other operating conditions, plastic damage will inevitably occur, and then fracture and failure will lead to leakage accidents.In order to evaluate the damage degree of pipeline steel and judge the service status, it is urgent to carry out the plastic damage detection technology of pipeline steel. This paper discusses the problem of plastic damage of X80 pipeline steel by simulation. The simulation model of nonlinear ultrasound mixing detection are verified with the experiment which was performed based on RITEC RAM-5000 SNAP, and the maximum absolute error was 0.3×10^-3. According to the finite element analysis of nonlinear mixing ultrasound, it is known that the nonlinear parameter <i>β</i> will increase with the increase of the degree of plastic damage of the material. Therefore, the nonlinear mixing ultrasonic signal can effectively represent the degree of plastic damage of X80 pipeline steel. The research results provide a technical way to further evaluate the remaining life of oil and gas pipeline.