Fracture Toughness Testing Using Non-Standard PCVN Specimens: Experiments and Specimen Geometry Effects on T₀ Reference Temperature

This work addresses an experimental investigation on the cleavage fracture behavior of a high strength, low alloy structural steel using non-standard PCVN specimens. The primary purpose is to investigate the effects of increased specimen span on experimentally measured fracture toughness values and implications for the characterization of the temperature dependence of toughness based on the Master Curve methodology. Fracture toughness testing conducted on various PCVN geometries with increased specimen span extracted from an A572 Grade 50 steel plate provides the cleavage fracture resistance data in terms of the J-integral at cleavage instability, J_c. The experimental results show a potential effect of specimen span on J_c-values which can help mitigating the effects of constraint loss often observed in smaller fracture specimens. An exploratory application to determine the reference temperature, T₀, derived from the Master Curve methodology also provides additional support for using non-standard bend specimens in routine fracture applications.