Probabilistic Assessment of the State of Welded Pipeline Elements and Pressure Vessels with Detected Corrosion-Erosion Defects

The main assumptions of the physical and mathematical models of the compatible development of stress-strain state and voids of ductile fracture of welded pipeline elements and pressure vessels with local corrosion-erosion metal losses in weld area have been given to determine the characteristic features of limit state of defective structures. Methods for probabilistic estimation of stressed state of the structures from the point of view of fracture susceptibility have been developed. They are based on the integration of the calculated field of principal stresses within the framework of Weibull statistics. For a correct quantitative assessment of state of critical structures based on complex analysis of the limit state of steel pipelines under internal pressure and different temperatures, functional dependences of Weibull coefficients on metal properties were obtained. Following the typical cases of exploitation damage in the main and technological pipeline elements the specific features of limit state under the different exploitation conditions have been investigated.