The use of a modified critical plane model to assess multiaxial fatigue of steels with nonmetallic inclusions

The goal of this research is to investigate the detrimental effect of non-metallic inclusions on the fatigue strength of the AISI 4140 steel under multiaxial loading conditions. In order to do so, a multiaxial fatigue model based on the critical plane approach is coupled with Murakami’s √area model. The proposed adaptation is very easy to calibrate and can also account for the higher probability of existing a fatal small defect as the volume of stresses material increases. Experimental multiaxial fatigue data were generated and compared with the estimates provided by the adapted multiaxial fatigue model and with its original version. The errors found are not higher than 10%.