A novel semi-analytical method based on equivalent energy principle to obtain J resistance curves of ductile materials

摘要

Four kinds of configurations represented by compact tension (CT) specimen, single edge-notched bending (SEB) specimen, single edge-notched tension (SET) specimen and C-shaped inside edge-notched tension (CIET) specimen were simulated by ANSYS 14.5 under plane strain conditions and three dimension (3D) conditions for determining the parameters of load-displacement, J integral-load etc. semi-analytical expressions. And a novel semi-analytical method is proposed to obtain J resistance curves of ductile materials on the basis of equivalent energy principle. In order to examine the validity of semi-analytical expressions, the fundamental curves (e.g., load-displacement, J integral-load curves etc.) predicted by the expressions were compared with the curves obtained from finite element analysis (FEA). It can be observed that they agree well with each other. Moreover, the real-time crack length and J integral of growing cracked specimen at arbitrary loading points can be determined through solving the explicit expressions. And a corrected formula of J integral was obtained in order to consider the influence of crack growth of sharp cracked specimen. Further, the J resistance curves of Cr2Ni2MoV for CT specimens and 26NiCrMoV11-5 for CIET specimens were successfully obtained via the new method, which show good agreement with the results determined by traditional normalization method. And the crack lengths predicted by the method match with those obtained by physical measurement on the fracture surface of specimens. Meanwhile, the critical Jc which represents the sharp cracked specimen beginning to growth can also be easily determined.