Estimation of Residual Strength and Residual Fatigue Life of Damaged Steel Plate

Abstract: Cracks can form due to fatigue or they can exist as a consequence of manufacturing processes such as deep machining marks or voids in welds and metallurgical discontinuities such as foreign particle inclusions. Nucleation and propagation of cracks caused by repeated cyclic loading below the yield stress of a material may cause catastrophic failure. As the crack forms and grows under cyclic loading, the residual strength and residual fatigue life decreases. In the present study, relevant analytical, experimental and numerical methods are used for predicting the ultimate strength and residual fatigue life of a cracked steel plate element under axial tension, where cracking damage is treated as a parameter of influence is studied. In fatigue life estimation process of cracked steel plate element, Linear Elastic Fracture Mechanics (LEFM) is introduced to describe and predict fatigue crack growth life and fracture under the basic assumption that material conditions are predominantly linear elastic during the fatigue process. The objective of this analysis is to predict crack growth, residual strength and residual fatigue life for the given initial damage on Critical Structural Element (CSE). Information on the growth of cracks in engineering structures and the residual strength of cracked structures is necessary for prediction of service lives of structures subjected to fatigue loading and for the establishment of safe intervals.

Keywords: Residual Strength, Linear Elastic Fracture Mechanics (LEFM), Residual Life, Stress Intensity Factor (SIF), Crack Growth Analysis