In the current work, the comprehensive combined effects of thermal aging, and 3D in-plane and out-of-plane constraints on the fracture resistance curves (J-R and CTOD-R) of reactor pressure vessel (RPV) steel, 16MND5 were investigated. &nbsp;First, the fracture experiments of RPV steel with different thermal aging durations using variously sized clamped single edge notched tension (SENT) specimens, were summarized. &nbsp;Then, three-dimensional finite element method (FEM) was used to determine the constraint parameters for the test specimens. &nbsp;From the analysis results, it was shown that the normalized T11, and the independent portion of T33 can accurately quantify the in-plane and out-of-plane constraint levels, respectively. &nbsp;Next, the in-plane and out-of-plane constraint-quantified R-curves were developed. &nbsp;Results showed that the effects of thermal aging, in-plane and out of-plane constraints on fracture toughness present significant interactions. &nbsp;The specific characteristics observed are: the influence of constraints on fracture toughness decreases with the increase of thermal aging duration, especially the in-plane constraint effect; the effect of thermal aging on fracture behavior is more significant under low constraint conditions. &nbsp;Further, the current in-plane and out-of-plane constraint dependent R-curves can easily reproduce all tested R-curves determined by clamped SENT specimens. &nbsp;It was also shown that they can accurately predict R-curves of new tested pin-loaded SENT specimens or real RPV cracked structures under different thermal aging durations.

Application of 3D Constraint-Based Fracture Mechanics for the Determination of R-Curves of Thermal Aged 16MND5 Steel

Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2021/volume/85314

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