Analysis of stress ratio effects on fatigue propagation in a sintered duplex steel by experimentation and artificial neural network approaches

The phenomenological approach to fatigue crack propagation through Paris-like models does not allow consideration of the influence of all the variables. The load ratio R (load minimum/load maximum) is one of the commonly considered parameters and, although many attempts have been made with the aim to identify the different mechanisms that depend on R (e.g. crack closure effects), this parameter is still used as an additional input in many applications. In this work the influence of R on the fatigue crack propagation resistance in a PM duplex stainless steel was investigated and an artificial neural network based model was optimised as a new simulation tool.