Study on the Burst Pressure and Failure Mechanism of Pipelines with a Kinked Dent–Corrosion Defect Based on Element Birth and Death Technique

Existing studies on dent-corrosion defect suffer from two main limitations. First, the simulation approach of imposing a dent onto a precorroded pipe fails to replicate the actual sequence of defect formation. Second, there is a lack of research on the more prevalent and hazardous kinked dent-corrosion defect. To address these gaps, this study innovatively employed the element birth and death technique to accurately simulate the sequential formation of a kinked dent followed by corrosion. A high-fidelity model of a pipeline containing a kinked dent-corrosion defect was developed. Using this model, the burst pressure, failure mechanisms, and parameter sensitivity were systematically investigated. The results show that burst pressure exhibits a significantly negative correlation with the outer diameter (D), dent depth (d), corrosion length (l), and corrosion depth (δ), while showing a significantly positive correlation with the indenter radius (r) and wall thickness (t). When the d exceeds a critical value (dc) or the r falls below a critical value (rc), the dominant failure factor shifts from corrosion to the dent itself, accompanied by a sharp increase in the sensitivity of burst pressure to dent parameters. For instance, at r=2%D and d=10.7%D, the burst pressure decreases by 17% compared to the baseline parameters. Moreover, a reduction in indenter radius significantly reduces both the critical and maximum dent depths. Specifically, as r decreases from 10%D to 2%D, dc decreases from 10.7%D to 6%D, and the maximum dent depth (dmax) declines from 15.3%D to 10.8%D. The influence of dent depth on burst pressure is strongly intensified by a reduction in indenter radius. Similarly, the influence of indenter radius becomes more pronounced as the dent depth increases.