The effect of the yield to tensile strength ratio on stress/strain concentrations around holes in high-strength steels

Application of high-strength steels in the maritime and offshore industry is currently limited by rules governing the ratio of the yield to tensile strength (the Y/T ratio). To better understand the physical basis for these rules, the nature and extent of the plastic stress/strain field in the vicinity of a stress concentration (a circular hole) in a structure made from high-strength steel are analyzed. This is done through analytical models of the stress field and the extent of plasticity in the vicinity of a hole based on classical methods. These analytical methods are validated through FEA models that are in turn validated by published experimental data. This paper concludes that a high Y/T ratio leads to a lower plastic SCF and a higher local strain in the vicinity of a hole. The extent of the plastic zone is not affected by different values of Y/T ratio for different values of σ_nom/σ_y.