On the notch effect in load bearing capacity, apparent fracture toughness and fracture mechanisms of polymer PMMA, aluminium alloy Al7075-T651 and structural steels S275JR and S355J2

This paper presents an analysis of the notch effect in the load bearing capacity, the apparent fracture toughness and the fracture mechanisms of four different materials: polymer PMMA, aluminium alloy Al7075-T651, and structural steels S275JR and S355J2 within their corresponding ductile-to-brittle transition zone.

Concerning the load bearing capacity and the apparent fracture toughness, a clear notch effect has been observed. In the case of the apparent fracture toughness, this has been adequately predicted here through the Theory of Critical Distances.

As for fracture mechanisms, it is shown how these progressively change with the notch radius, from basically brittle ones in cracked conditions, to non-linear mechanisms observed for higher notch radii. This evolution has been observed in the four analysed materials and, in all cases, has justified the corresponding consequences of the notch effect on both the load bearing capacity and the apparent fracture toughness.