Comparison of fatigue resistance of dog-bone and hourglass-shaped Hardox 450 steel specimens

This study compares the fatigue resistance of two standardized specimen geometries -dog-bone and hourglass-shaped -made from Hardox 450 high-strength steel.Rotating bending fatigue tests evaluated differences in fatigue durability.Strain gauge measurements and the FEM analysis showed hourglass specimens had more uniform stress distribution and lower concentration effects.Fatigue tests revealed an 8 % higher fatigue limit for the hourglass specimens, probably due to the lack of localized stress concentration at the transition between the radius and the cylindrical section.These findings contribute to understanding how standardized specimen geometries influence fatigue performance.