Rapid Stress Intensity Factor Evaluation in Cracked Welded Joints

Abstract

Accurate determination of stress intensity factors (SIFs) and nonlinear local stress fields in welded plate joints is essential for fatigue life prediction and structural integrity assessment. However, finite element simulations become tedious and computationally expensive when dealing with complex crack geometries, particularly in real-time monitoring or large-scale engineering applications. This study presents a hybrid analytical-optimization framework that integrates analytical structural mechanics with genetic optimization to determine nonlinear local stress fields and stress intensity factors (SIFs) for welded plate joints. The framework formulates a physics-informed objective function derived from global force-moment equilibrium, enabling accurate identification of nonlinear regions and crack-tip parameters for through-width, shallow/deep elliptical, and highly irregular crack geometries. By embedding curvature radius, crack-front orientation, and geometry-dependent stress characteristics into a unified optimization procedure, the proposed method reproduces FEM-level accuracy while reducing computational cost by orders of magnitude.