Influence of strain rate on the nature of failure under prolonged static and cyclical loads. 2. Examples of calculation

Based on a physicomechanical model of intercrystallite failure in materials, such as presented in the previous communication, we have proposed a computational algorithm for the endurance of polycrystalline material under cyclical load. We have provided examples for the calculation of the cyclical strength in austenitic steel under various strain rates. Comparison of the theoretical results against the experimental data demonstrated the possibility of using the model developed here to describe the quantitative relationships governing intercrystallite failure of the material over a broad range of load regimes.Translated from Problemy Prochnosti, No. 8, pp. 42–47, August, 1991.     

A New Engineering Method for Prediction of Fracture Toughness Temperature Dependence for Pressure-Vessel Steels

An engineering method called Unified Curve, which is similar to the Master Curve approach, is proposed for predicting the temperature dependence of the static fracture toughness for steels of various degrees of embrittlement (up to a very high one). The Unified Curve method has been extensively tested, and a comparison has been made between these two methods. The Master Curve is shown to be a particular case of the Unified Curve method.     

A new engineering method for prediction of the fracture toughness temperature dependence for RPV steels

In order to predict the temperature dependence of fracture toughness for RPV steels with various degrees of embrittlement, up to extremely high levels, an engineering method is proposed which is similar to the Master Curve concept and named the Unified Curve concept. Wide verification of the Unified Curve concept is performed and comparison of the Master and Unified Curve concepts is carried out. It is shown that the Master Curve concept is a partial case of the Unified Curve concept.     

Modeling for fracture in materials under long-term static creep loading and neutron irradiation. Part 1. A physico-mechanical model

The paper presents a physico-mechanical model for predicting creep rupture in neutron-irradiated materials. The model is based on the approach whereby damage is described as voids on grain boundaries. The equations for void nucleation and growth which were proposed by the authors earlier are augmented to include neutron irradiation of material. Constitutive equations are derived to describe viscoplastic deformation of material including void propagation. A criterion for plastic stability of a unit cell is employed as a fracture criterion. __________ Translated from Problemy Prochnosti, No. 3, pp. 5–22, May–June, 2006.     

A comparative analysis of radiation-thermal forming for reflectors of reactors BN-600 and BN-800 by results of numerical simulation

The results of numerical simulation of radiation-thermal forming for bearing shells of reflectors for reactors BN-600 and BN-800, made of various austenitic steels, with the help of parameters of models for radiation swelling, radiation creep, and plasticity, are presented. Based on an analysis of the results, we show that the radiation change in basic dimensions, which characterizes the efficiency of the reactor BN-800 reflector made from austenitic steel Kh16N11M3, is significantly lower than changes for similar sizes for the reactor BN-600 reflector made from steel Kh18N9.     

Probabilistic prediction of the crack resistance of nuclear pressure-vessel steels on the basis of a local approach. Part 2

On the basis of a new local probabilistic criterion of brittle fracture, a local criterion of ductile fracture proposed by the authors earlier, and the obtained approximate solution of the problem of stress-strain state near the crack tip, we develop a probabilistic model for the prediction of the crack resistance of pressure-vessel steels. The model enables one to predict the dependence of K _Ic on temperature for any given probability of brittle fracture and the influence of the thickness of the specimen on K _Ic. Bu using this model, we can also describe the temperature range of the brittle-ductile transition. The results of numerical calculations are compared with the experimental data for 15Kh2MFA pressure-vessel steel. It is shown that the proposed model fairly well describes the spread in the experimental data on the crack resistance of this type of steel. TsNII KM “Prometei,” St. Petersburg, Russia. Translated from Problemy Prochnosti, No. 2, pp. 5–22, March–April, 1999.