Fatigue in High-Speed Ships: Crack Propagation in Aluminum

摘要

To develop a design method concerning high-cycle fatigue of arc-welded joints in high-speed aluminum ships, two-stage crack growth, micro-crack and macro-crack growth, propagation, in aluminum 5083 has been investigated using a Linear Elastic Fracture Mechanics (LEFM) approach. The macro-crack growth governing LEFM parameter, the Stress Intensity Factor (SIF), is obtained using available handbook solutions. This SIF is corrected using the Stress Concentration Factor (SCF) related analytical, parametric notch stress formulations of the uncracked geometry of the welded joints, applied as crack face pressure, to cover micro-crack growth. The notch stress formulations and SIF's for some basic welded joints are compared to Finite Element (FE) solutions and match quite well. The two-stage crack growth model is compared to experimental data of a Single Edge Notch (SEN) specimen and show promising results.