Prediction of the Low-Cycle Fatigue Life of HY-100 Undermatched Welds in Marine Structures
Finite-element and analytical models are used in this study to predict the low-cycle fatigue life of undermatched (lower yield strength) weldments of HY-100 steel. The objective was to determine the feasibility of replacing conventional overmatched welds in marine structures. Fatigue tests were performed on standard, smooth specimens, notched cylindrical specimens and a four-point-bend test on a full-scale butt beam specimen. Numerical analyses were conducted using finite elements, with a two-surface plasticity algorithm to simulate the cyclic behavior of the individual materials. The stress and strain concentrations at the notches were also evaluated using two analytical models: the Neuber and Glinka relations. The finite-element predictions compared well with experimental data and produced detailed predictions of the strain distributions, which were then used to assess the crack initiation life. Glinka's relation demonstrated superior predictive capabilities for local strains over Neuber's relation.