Experimental Measurements of J c-Values for a Low Alloy Structural Steel Using Nonstandard Bend Specimens and Evaluation of the Reference Temperature, T

Abstract This work experimentally investigates the cleavage fracture behavior of a high strength, low alloy structural steel using standard and nonstandard single-edge notched bend specimens, including nonstandard precracked Charpy-type configurations tested under three-point bending. The primary purpose of this study is to investigate the effects of geometry and loading mode on fracture toughness using nonstandard bend specimens under three-point and four-point loading. Fracture toughness testing conducted on various bend specimen geometries extracted from an ASTM A572, Standard Specification for High-Strength Low Alloy Columbium-Vanadium Structural Steel, Grade 50 steel plate provides the cleavage fracture resistance data in terms of the J-integral at cleavage instability, Jc. The experimental results show potential effects of specimen geometry and loading mode on Jc-values that can help to mitigate the effects of constraint loss often observed in smaller fracture specimens. An exploratory application derived from the master curve methodology to determine the reference temperature, T0, also provides additional support for using nonstandard bend specimens in routine fracture applications.