A phenomenological form of the q{sub}2 parameter in the Gurson model

摘要

Continuum damage mechanics is applied to compute fracture J-initiation and the J-resistance (J-R) curve for SA333 Gr.6 carbon steel material. A parametric study is carried out to assess the effects of variation of Gurson material parameters on the J-R curve. A difficulty is experienced to obtain a set of Gurson parameters that can compute J-initiation as well as the entire J-R curve close to the measured values. It has been found that a phenomenological form of the q{sub}2 parameter, used in the Gurson constitutive model, based on experimental observation helps to overcome this difficulty. The new form of q{sub}2 has an exponential spatial variation near the crack tip and has two constants. These additional constants help analysts to compute the complete J-R curve (including J-initiation) close to experimental data. The same set of constants has also been found to be useful for other fracture specimens, materials and two piping components of a nuclear plant.