This work studies the feasibility of proposing a methodology to characterize the fracture resistance curves of materials, such as pipeline steels used in the oil and gas industry, using four-point (4PT) bending specimens. The methodology will be defined by obtaining the equations of flexibility, the stress intensity factor, a proportionality factor between the strain energy and the-integral, known as factor, and the dimensionless factor that accounts for the effects of ductile crack growth, known as factor. Also, this work will show the geometry effects on crack tip constraint by using the J-Q theory. The 4PT geometry presents an evolution in the crack-tip stress triaxiality, which is similar to circumferentially cracked risers. The main contribution of this research is the detailed methodology for calculating fracture toughness curve using samples with square or rectangular cross section under four-pointbending loading. In addition, experimental test were carried out using to validate the proposed methodology testing four-point bending specimens. The results were compared with experimental data coming from standardized geometries SE(B) and SE(T). The experiments validated the numerical analyzes. Therefore, the equations proposed here can be used to measure the fracture toughness of steels by testing four-point bending specimens.
This work proposes a new test methodology to characterize the fracture toughness values for either brittle or ductile materials, such as steels of risers and pipelines used in the oil and gas industry by using non-standard four-point bending specimens. Four-point bending (4PB) specimens show to be reliable configuration to characterize fracture toughness values. The methodology involves obtaining compliance equations, stress intensity factors, the proportionality factors between the deformation energy and J-integral, known as η-factor. This study evidences the impact of geometry variation on the crack-tip constraint. Laboratory tests were performed with four-point bending specimens. These experiments were compared with experimental data of standardized geometries SE(B) and SE(T). The results from the preliminary experimental campaign validated the numerical analysis. Thus, the proposed equations can be used to obtain the fracture toughness values using four-point bending specimens.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.