Analysis of Radiation Creep Problems Considering Pore Growth Ductile Fracture by Rice–Tracey–Huang Models and Kachanov's Solution for a Spherical Cavity. Part 1. Initial Preconditions and Models for the Formulation of the Governing Equations.

Applying the Rice–Tracey–Huang models and Kachanov's equilibrium solution of a spherical cavity to the analysis of the ductile fracture pore concentration growth in a material subjected to neutron irradiation is considered. The generalized equation combines the classical Rice–Tracey–Huang equations and includes the modified Huang equation, in which an additional continuous function greater than zero is introduced, which depends on the stiffness of the stress state and has a nonnegative derivative. With this modification of the classical Huang equation, the properties of the governing equations for the analysis of the porosity of irradiated material are improved, which contributes to the weakening of the limitations of the initial data associated with the stiffness of the stress state. The generalized Rice–Tracey–Huang equation is considered to model the process of pore concentration growth in a rigid-plastic material. The equation derived from Kachanov's solution for a spherical cavity is proposed to analyze the porosity in an elastic-plastic material with radiation creep. The application of Kachanov's solution to model the growth of pore concentration allows us to consider the radiation creep in the elastic region of the strain diagram of the irradiated material, in contrast to the classical Rice–Tracey–Huang equations, in which the elastic region is not considered. Taking into account this factor affects the results of the analysis of the behavior of porous material, since with increasing radiation dose, radiation hardening occurs, which leads to a decrease in the plasticity of the material, and therefore, under prolonged neutron irradiation, the role of elastic strain and radiation creep in the elastic region of the strain diagram increases. Based on the obtained relations, which follow from Kachanov's solution, the equation to describe the growth of the volume concentration of pores in the material depending on the increments of instant plasticity and radiation creep strains is formulated. Modern models of radiation swelling and radiation creep are used, which take into account the damaging dose, irradiation temperature, the influence of the stress state and the accumulated irreversible strain on the processes of swelling and creep of the irradiated material. [ABSTRACT FROM AUTHOR]