Further improvement of the Prometey model and Unified Curve method part 1. Improvement of the Prometey model

• Published in: Engineering fracture mechanics Vol. 182; pp. 467 - 486
• Main Authors: Margolin, B.Z., Fomenko, V.N., Gulenko, A.G., Kostylev, V.I., Shvetsova, V.A.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01-09-2017; Elsevier BV
• Subjects: Brittle fracture; Brittle fracture probability; Data transfer (computers); Local approach; Probabilistic models; Probability; RPV steel; Statistical analysis; Steel; Studies; Transferability; Brittle fracture probability; Transferability; RPV steel; Local approach
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2017.05.015

•We solve the transferability problem of brittle fracture data in local approach.•We modify the cleavage microcrack nucleation condition.•We deduce equations for fracture probability calculation for nonradial loading.•We compare the calculated and experimental results for various specimens from RPV steel in various conditions.•The modified Prometey model predicts the brittle fracture for various specimens with the same model parameters.
The local approach to brittle fracture is able in principle to transfer fracture data from one type of specimens to another one for different test temperatures and different material conditions. However, in practice the capacity of existing models to perform transferability need to be improved. For this reason the probabilistic model of brittle fracture known as the Prometey model has been modified. The modified model (referred to as the Prometey-M model) has been used for analysis of the transferability of the experimental results on brittle fracture for smooth and notched cylindrical tensile specimens and cracked specimens from Reactor Pressure Vessel (RPV) steel in the initial and embrittled conditions. The Prometey-M model allows the calculation of the brittle fracture probability with the same model parameters for specimens of different types tested at different temperatures. Recommendations have been given for the parameter values of the Prometey-M model that may be taken the same for RPV steels in the initial and embrittled conditions.