Papers by Author: Insu Jeon

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Authors: Sung Hyun Lee, Insu Jeon
Abstract: It is important to evaluate the 3D crack behavior in the structures. In this study, a Crack-growth test and two simulations namely, Real-model simulation and Ideal-model simulation were performed using eXtended Finite Element Method (XFEM) to evaluate crack behavior three-dimensionally. In the Crack-growth test, crack behavior was observed for a notched metal specimen. In the Real-model simulation, the FE model was constructed using a 3D reconstruction model of the specimen, and crack growth was simulated. In the Ideal-model simulation, the simulation was performed using the FE model that involved ideal notch. The obtained crack growth simulation results were compared with tension test result. Crack growth in the specimen was evaluated three-dimensionally. It was shown that modeling the real shape of a structure with a crack may be essential for accurately evaluating 3D crack growth.
278
Authors: Insu Jeon, Masaki Omiya, Hirotsugu Inoue, Kikuo Kishimoto, Tadashi Asahina
Abstract: A new specimen is proposed to measure the interfacial toughness between the Al-0.5%Cu thin film and the Si substrate. The plain and general micro-fabrication processes are sufficient to fabricate the specimen. With the help of the finite element method and the concepts of the linear elastic fracture mechanics, the detailed structure for this specimen is modeled and evaluated. The results obtained from this research show that the proposed specimen provides efficient and convenient method to measure the interfacial toughness between the Al-Cu thin film and the Si substrate.
521
Authors: Tsutomu Sonoda, Kenji Katou, Insu Jeon, Yasuo Yamada, Tadashi Asahina
Abstract: Fabrication of sintered compact from aluminum powder coated with tin deposits was examined, in order to enhance the bonding among the aluminum particles under the assistance of tin and thereby the sintering effect of the aluminum powder, aiming at improving the mechanical properties of sintered aluminum materials. For the coating of aluminum powder with tin deposits, the deposition of pure tin onto the aluminum particles was carried out by magnetron DC sputtering during the self-convective motion of the aluminum powder in a vacuum chamber. The tablet consisting of the aluminum powder coated with tin deposits was sintered at 650°C in a vacuum chamber for 2 hours, while the tablet consisting of non-coated aluminum powder was also sintered under the same condition for comparison. The sintered compact from the coated aluminum powder was solid and uniform, and its consolidation reached over 95% while that from non-coated aluminum powder was around 85%. According to tensile tests, the tensile strength of the sintered compact from the coated aluminum powder was 75.4N/mm2 while that from non-coated aluminum powder was 71.0N/mm2, and the elongation of the sintered compact from the coated aluminum powder reached over 20% while that from non-coated aluminum powder was around 10%. Therefore it was found that the consolidation and the mechanical properties of the sintered compact consisting of aluminum powder were considerably improved by this powder coating process.
353
Authors: Y.P. Lee, Insu Jeon, Jun Hwa Hong, J.H. Moon, J.I. Jeong, J.S. Kang
411
Authors: Tadashi Asahina, Insu Jeon, Kiyotaka Katou, Tsutomu Sonoda
Abstract: The cell-structure of highly porous aluminum material prepared by melt foaming technology was investigated under deformation with fine-focus X-ray 3D-CT to make clear the development target porous material for automobile industries with improved reliability. It was confirmed that structures with more fine, more uniform and exclusion peculiar anisotropic pores would make improved mechanical properties of the material.
1395
Authors: Tadashi Asahina, Insu Jeon, Kiyotaka Katou, Tsutomu Sonoda
Abstract: The cell-structure of highly porous aluminum material prepared by foaming of aluminum alloy melt with titanium hydride was investigated nondestructively with fine-focus X-ray 3D-CT at several interrupt steps during slow compressive deformation. The foamed highly porous aluminum has anisotropic shape of each cell inevitably because of gravity force during solidification of foamed material and mechanical properties especially the dependence on the deformation direction of highly porous aluminum is analyzed well from the size and shape of each void composing the porous material. The statistic anisotropic distribution of these form factors such as three axial lengths and directions at the time of ellipsoidal approximation of each cell was found to be less important to improve the mechanical properties of this type of material.
1665
Authors: Hyung Seok Yoon, Insu Jeon
Abstract: The manufactures of the ultra-thin and smaller semiconductor chip are required over the portable electric devices. The investigation of Fan-out wafer level package (FOWLP) is used widely, among the performance improvement and miniaturization technologies. In this paper, we obtained lots of crack near the passivation (PSV) and redistributed layer (RDL) region of FOWLP during the reliability evaluation of thermal cycling test (TCT). The generated stress and deformational behavior was observed through 2D finite-element analysis. The concentrated stress and deformational behavior are observed around the Solder ball edge and RDL & PSV edges. The crack was observed experimentally as well. The verification of the mechanism for crack generation and the validity of the finite-element analysis were verified by the structural analysis.
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