• Journal of Ocean Engineering and Technology
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• v.29 no.6
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• pp.454-462
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• 2015

An extended study was conducted on the fracture criterion by Choung et al. (2011; 2012) and Choung and Nam (2013), and the results are presented in two parts. The theoretical background of the fracture and the results of new experimental studies were reported in Part I, and three-dimensional fracture surface formulations and verifications are reported in Part II. How the corrected true stress can be processed from the extrapolated true stress is first introduced. Numerical simulations using the corrected true stress were conducted for pure shear, shear-tension, and pure compression tests. The numerical results perfectly coincided with test results, except for the pure shear simulations, where volume locking appeared to prevent a load reduction. The average stress triaxialities, average normalized lode parameters, and equivalent plastic strain at fracture initiation were extracted from numerical simulations to formulate a new three-dimensional fracture strain surface. A series of extra tests with asymmetric notch specimens was performed to check the validity of the newly developed fracture strain surface. Then, a new user-subroutine was developed to calculate and transfer the two fracture parameters to commercial finite element code. Simulation results based on the user-subroutine were in good agreement with the test results.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.213-214
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• 2023

In a paper reporting the introduction and settlement of Anoplophora horsfieldii (Hope) into Jeju, it was found that Bactrocera dorsalis (Hendel) was misquoted as "it was introduced into the Jeju area and is currently being discovered." Fortunately, the sentence was quickly discovered and corrected to "it has the potential to be introduced to Jeju Island". Taking this as an opportunity, we would like to emphasize to researchers that it is necessary to verify very carefully when describing the domestic distribution of prohibited quarantine pests. Estimating by the cold stress index of the CLIMEX model, B. dorsalis was predicted to be unable to survive in Jeju in the winter of 2022-2023. However, in the winter of 2023, it was confirmed that the occurrence of A. horsfieldii was found to occur in the summer after overwintering at sub-zero temperatures, and it was judged to have succeeded in settling.