Experimental determination and numerical validation of the critical value of the J-integral ofa low carbon microalloyed steel for elevated temperature application

Abstract

To evaluate the behavior of a homogeneous material in the presence of a crack-type defect, the value of the critical stress-intensity factor, KIc, was determined as a measure of the fracture toughness of the tested steel under the conditions of a plane stress state, at two test temperatures, 20 C and 540 C. The experiments were carried out using the method of testing one specimen with successive partial unloading, which aims to r occurs during the test. In addition to the experimental analysis, a numerical simulation of the behavior of the specimens under static and dynamic loading was performed. The numerical analysis is based on the experimentally obtained yield strength and tensile strength values of the investigated steel, and was done in Ansys Workbench R21 software package, which relies on finite element method, FEM. The results obtained by numerical analysis showed good agreement with the experimentally obtained results of the J-integral for specimens tested at room and elevated temperature. Good agreement with the experimental results was shown, confirming the use of FEM for the load cases considered.