In recent years an increasing interest has been shown in materials characterisation techniques based on the use of reduced dimension samples. One of these techniques, first developed in the early 80’s, is Small Punch testing, in which a punch acts over a plane small specimen deforming it until fracture. So far, this test has been used as a tool for the estimation of mechanical properties, for characterising ductilebrittle transition or for knowing the evolution of these properties with ageing phenomena as neutron irradiation. The Small Punch Test has even been used in the determination of fracture toughness by means of indirect correlations or complex methodologies based on damage models and Finite Element simulations. In this paper, a direct methodology for the determination of fracture toughness from Small Punch tests is proposed. The approach is based on the use of simply modified Small Punch specimens in which a lateral notch was machined. Attending to energy considerations, the J-Δa curve for a ship-building Grade A steel, as well as for a structural steel, E690, has been obtained using this type of samples and the results have been compared with the calculated results from conventional fracture tests.
Determination of Fracture Toughness Characteristics of Small- Size Chevron-Notched Specimens
