3D fractal modeling of non-uniform corrosion in steel pipes: Failure behavior analysis and structural integrity assessment
针对传统理想化几何假设评估腐蚀钢管失效压力的局限，提出结合三维分形理论与有限元建模的方法，模拟随机非均匀腐蚀缺陷的力学行为，并通过全尺寸爆破试验验证，揭示了分形特征与失效压力的关联。
To address the limitations of conventional idealized geometric assumptions in evaluating the failure pressure of corroded steel pipes, this study proposes an integrated methodology combining three-dimensional (3D) fractal theory with finite element (FE) modeling to characterize the mechanical behavior of random non-uniform corrosion defects. A random non-uniform corrosion pipe model was developed by reconstructing corrosion morphologies using the Weierstrass-Mandelbrot (W-M) fractal function within a Python-ABAQUS collaborative framework, incorporating fractal dimension ( D n ), spatial frequency ( γ ), and scale coefficient ( C n ). The model's reliability was validated through full-scale burst tests. Systematic quantification revealed the correlation between geometric parameters of single-point defects, spacing of double-point defects, and failure behavior. The results demonstrate that under single-point corrosion conditions, increasing the defect length to 180 mm and depth to 0.8 t reduces failure pressure by 15.99 % and 23.66 %, respectively. Conversely, widening the corrosion angle to 40° reduces failure pressure by only 7.85 % through stress dispersion effects. For double-point corrosion interaction, longitudinal spacing exerts a significantly stronger influence on defect coupling than circumferential spacing. Critical spacings (1.5 D t for longitudinal alignment and 0.16π D for circumferential alignment) effectively isolate interaction effects. This study establishes a systematic correlation framework between fractal characteristics and mechanical responses, advancing a theoretical paradigm for the reliability assessment of corroded pipelines.