Effect of multiaxial bending-torsion loading on fracture surface parameters in high-strength steels processed by conventional and additive manufacturing

This paper studies the effect of multiaxial loading scenario on surface topography in notched samples made of high-strength steels processed by both conventional and additive manufacturing techniques. In a first stage, combined bending-torsion fatigue tests are performed for three bending-to-torsion ratios. In a second stage, based on the entire total area method, fracture surfaces are analysed via different surface topography parameters, namely height parameters, material/void volume parameters. The results show that surface topography parameters are decreasing functions of the bending-to-torsion ratio and the fatigue life, as well as increasing functions of von Mises stress range. Linear relationships between the surface topography parameters and the bending-torsion ratio, the fatigue life, and the von Mises stress range were found.