Assessment of plastic damage of duplex X80 pipeline steel based on ultrasonic longitudinal wave

With the continuous extension of oil pipelines to polar, ocean and geological unstable areas, the failure behaviors related to local flexion, instability and ductility fracture are easy to occur under the action of operating conditions such as high pressure and large deformation. The quantitative detection of the plastic damage degree of pipeline steel material needs to be further discussed. In this project, the typical bipolar pipeline steel is taken as the research object, and the GTN thin damage model is used to describe the plastic damage of pipeline steel, analyze the influence of thin structure on the deterioration of the mechanical properties of materials; The ultrasonic technology was introduced to detect the plastic damage degree of pipeline steel, and the correlation between ultrasonic wave speed and the volume fraction of the damage variable f was studied, and the correlation model between the plastic damage behavior and ultrasonic speed of pipeline steel material was established. provides a basis for quantitative assessment of plastic steel and safe service status of pipeline.