Papers by Author: Jung Hun Choi

Abstract: In case of large steel water pipe, it have been observed that its fracture mostly occurs due to the complicated outside fatigue load on the pipe in the underground. It is also well known that its damage and leakage happen mainly in a weld zone. In this study we evaluated the fatigue characteristics based on size effect and residual stress by comparing the test results on the standard specimen collected from real pipe with those on full scale pipe.

Abstract: In this study, we performed thermal stress analyses on a ventilated disk brake with a 3D model for two cases (whether the pressure distribution on a contact surface is uniform or not). A pressure distribution analysis was performed to determine the pressure distribution on the contact surface. Then, by using the results that were obtained from the pressure distribution analyses, we performed thermal stress analyses. Finally, we have found the spots where the maximum thermal stresses occur. Also, for the life evaluation of a disk brake, we have conducted the fatigue test and obtained the S-N curve. From those results, we evaluated the life of a disk brake.