Identification of ductile damage parameters for pressure vessel steel

The FEM simulations in the field of design and safety assessment represent very powerful tools, but they are strongly limited by available material models and material input data. If states near to ductile fracture are to be considered, more complex material description taking into account multiaxial loading conditions is necessary. As complex material models suitable to include these effects into practical simulations are still mostly phenomenological, experiments with samples of various geometries tested under various loading modes have to be used. On the basis of these tests a complex material behavior model covering elastic and plastic material behavior for various stress states can be obtained. This kind of the material behavior description allows a wide range of application from calculation of component limit loading conditions to material properties conversion for samples of different sizes e.g. This paper deals with ductile damage parameters determination for two typical Reactor Pressure Vessel (RPV) steels ferritic and austenitic. The ferritic steel is used for the RPV vessel and the austenitic one is used for internals. There are chosen appropriate samples geometries based on the preliminary FEM stress state analyses of samples at first. Subsequently, testing of proposed samples is performed and material parameters are evaluated. The obtained material plastic damage parameters are subsequently applied to FEM simulation of sharp notched samples and capabilities of applied models to describe material behavior for high stress concentrations is assessed on the basis comparison with real tests. (C) 2016 Elsevier B.V. All rights reserved.