جستجوی مقالات مرتبط با کلیدواژه "مدل گرسون" در نشریات گروه "مکانیک"

Plain strain fracture toughness is extremely important for failure assessment in high strength steels used in gas transmission pipelines. In the current research an experimental method based on three point bend test specimens was used to calculate fracture toughness of steel pipes of grade API X65 (with outer diameter of 1219 mm and wall thickness of 14.3 mm). A value of 308 MPa√m was found for fracture toughness of test material. Then a finite element solution for the test specimens was conducted using modified Gurson’s damage theory. In this model, the critical crack tip opening displacement was calculated from damaged elements in the early stage of crack growth. This model resulted in 297 MPa√m of fracture toughness. A comparison between the experimental and numerical results illustrated the fitness of common methods for determining fracture toughness of tested steel in ambient temperature. Due to the lack of experimental data for this steel, the obtained results can be used for safe performance of domestic gas pipelines made from API X65 steel.

Plain strain fracture toughness is extremely important for failure assessment in high strength steels used in gas transmission pipelines. In the current research an experimental method based on three point bend test specimens was used to calculate fracture toughness of steel pipes of grade API X65 (with outer diameter of 1219 mm and wall thickness of 14.3 mm). A value of 308 MPa√m was found for fracture toughness of test material. Then a finite element solution for the test specimens was conducted using modified Gurson’s damage theory. In this model¡ the critical crack tip opening displacement was calculated from damaged elements in the early stage of crack growth. This model resulted in 297 MPa√m of fracture toughness. A comparison between the experimental and numerical results illustrated the fitness of common methods for determining fracture toughness of tested steel in ambient temperature. Due to the lack of experimental data for this steel¡ the obtained results can be used for safe performance of domestic gas pipelines made from API X65 steel.

In this paper, a method to determine the material parameters of the Lemaitre damage model from the knowledge of the Gurson model parameters is proposed. As for porosity damage, the Gurson model neglects the coupling of elasticity with damage, allowing to use the stress softening effect to make a link between both theories up to a fast identification procedure (based on the expressions of the yield surfaces of the damaged material). An experimental procedure to identify the Gurson damage parameters has been established for A533B alloy steel under stress triaxiality condition. This method is evaluated in the experimental results of A533B steel. The comparisons indicate good agreements between the result obtained by the proposed method and those of experiments.