In this paper, a local criterion is proposed to predict cleavage crack propagation and arrest in a Reactor Pressure Vessel (RPV) steel. The objective is to develop an accurate predictive model, applicable and validated in the conditions of a thermal shock on a RPV steel. A local stress based criterion has been proposed, derived from Ritchie Knott and Rice model. In this formulation, crack propagation and arrest are driven by a critical level of stress, at a given distance ahead of the crack tip. This critical stress has appeared to depend on temperature and plastic strain rate ahead of the crack tip. In the first step, by using 2D modelling in Cast3M software, with extended finite element method, this criterion has been identified on isothermal fracture tests, performed on Compact Tensile specimens at different temperatures in the brittle-to-ductile transition range. Then, in a validation step, the criterion has been successfully applied to predict the cleavage crack propagation and arrest on different specimen geometries, allowing mode I as well as mixed mode loadings and in both isothermal (at different temperatures) and anisothermal (i.e. thermal shock) tests. The results have therefore, demonstrated the transferability of the criterion for this steel, within a large range of thermal and mechanical loadings.
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