• Journal of KSNVE
• /
• v.10 no.2
• /
• pp.261-268
• /
• 2000

The instrumented capsule is subjected to flow-induced vibration(FIV) due to the flow of the primary coolant and then the structural integrity of the capsule during irradiation in the HANARO reactor is an issue of major concern. For this purpose the acceleration was measured by four accelerometers attached to the protection tube of the capsule mainbody and the displacement of test holes was calcultated using commercial finite element program ANSYS to evaluate the structural interference with the neighboring flow tubes under the reactor operating condition. The calculated displacements of test holes in the reactor in-core were found to be lower than the values of allowable design criteria.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.20 no.1
• /
• pp.9-18
• /
• 2007

This study shows an implementation of partial holes in an initial design domain in order to improve convergences of topology optimization algorithms. The method is associated with a bubble method as introduced by Eschenauer et al. to overcome slow convergence of boundary-based shape optimization methods. However, contrary to the bubble method, initial holes are only implemented for initializations of optimization algorithm in this approach, and there is no need to consider a characteristic function which defines hole's deposition during every optimization procedure. In addition, solid and void regions within the initial design domain are not fixed but merged or split during optimization Procedures. Since this phenomenon activates finite changes of design parameters without numerically calculating movements and positions of holes, convergences of topology optimization algorithm can be improved. In the present study, material topology optimization designs of Michell-type beam utilizing the initial design domain with initial holes of varied sizes and shapes is carried out by using SIMP like a density distribution method. Numerical examples demonstrate the efficiency and simplicity of the present method.

• Journal of Korea Society of Industrial Information Systems
• /
• v.25 no.3
• /
• pp.11-19
• /
• 2020

This study seeks to measure inter-industry convergence systematically and quantitatively using structural holes theory. ICT industries were classified into ICT manufacturing and ICT service then efficiency and constraints were calculated using input-output tables. The results of the study revealed both ICT industries have very high information and control benefits in the process of industrial convergence, proving to be key industries with competitive advantage. Further implications were presented based on comparative analysis between ICT manufacturing and service and trend analysis over the past 15 years.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2017.10a
• /
• pp.32-37
• /
• 2017

Due to the nature of semi-submergible drilling rig, various equipments are arranged in a limited space, and therefore the many types of outfitting holes passing through the hull structure are densely arranged and that is required the detailed structural strength evaluation in terms of ULS and FLS by class or client. Particularly, semi-submergible drilling rig has a variety of global load which affects the structure strength around holes compared to general commercial ship, and its response of stress is also complicated, so it is difficult to carry out the prediction design of structural strength evaluation and reinforcement. In this regard, this paper presents a case study on the evaluation of structural strength for the various holes and large openings of semi-submergible drilling rig conducted by our company, as well as an established hole verification procedure.

• Structural Engineering and Mechanics
• /
• v.58 no.3
• /
• pp.533-553
• /
• 2016

In this paper, the recently developed meta-heuristic algorithm called tug of war optimization is applied to optimal design of castellated beams. Two common types of laterally supported castellated beams are considered as design problems: beams with hexagonal openings and beams with circular openings. Here, castellated beams have been studied for two cases: beams without filled holes and beams with end-filled holes. Also, tug of war optimization algorithm is utilized for obtaining the solution of these design problems. For this purpose, the minimum cost is taken as the objective function, and some benchmark problems are solved from literature.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.6
• /
• pp.178-185
• /
• 2001

This paper describes the correlation between the interior noise and the trunk wall vibration. Using the vibro-acoustic reciprocity, effect of the trunk wall vibration on the compartment noise is investigated on a medium size car. In the low frequency range, vehicle interior noise is dominated by several acoustic modes of the passenger compartment and the vibration modes of the surrounding shell parts. Especially, vibration of the trunk wall radiates sound and it is transferred through holes on the package tray into the passenger compartment. This paper experimentally reveals that sound can be well produced at some particular vibration modes of the trunk lid and it strongly influences the compartment noise through package tray holes. Contributions of the trunk walls to the interior noise are estimated by measuring the acoustic-structural transfer function, based on the vibro-acoustical reciprocity theorem.

• Structural Engineering and Mechanics
• /
• v.26 no.5
• /
• pp.557-568
• /
• 2007

The elastic T-stress is increasingly being recognized as an important second parameter to the stress intensity factor for fracture and fatigue assessments. In this paper, the mutual or M-contour integral approach is employed in conjunction with the Boundary Element Method (BEM) to determine the numerical T-stress solutions for cracks in plates with multiple holes. The problems investigated include plates of infinite width with multiple holes at which single or double, symmetric cracks have grown from. Comparisons of these results are also made with the corresponding solutions of finite plates with a single hole. For completeness, stress intensity factor solutions for the cracked geometries analyzed are presented as well. These results will be useful for failure assessments using the two-parameter linear elastic fracture mechanics approach.

• International Journal of Precision Engineering and Manufacturing
• /
• v.7 no.2
• /
• pp.52-55
• /
• 2006

The OLEDs(Organic Light-Emitting Diodes) structure organizes the bottom layer using glass, ITO(indium thin oxide), hole injection layer, hole transport layer, emitting material layer, electron transport layer, electron injection layer and cathode using metal. OLED has various advantages. OLEDs research has been divided into structural side and emitting material side. The amount of emitting light and luminescence efficiency has been improved by continuing effort for emitting material layer. The emitting light mechanism of OLEDs consists of electrons and holes injected from cathode and anode recombination in emitting material layer. The mobilities of injected electrons and holes are different. The mobility of holes is faster than that of electrons. In order to get high luminescence efficiency by recombine electrons and holes, the balance of their mobility must be set. The more complex thin film structure of OLED becomes, the more understanding about physical phenomenon in each interface is needed. This paper observed what the thickness change of hole transport layer has an affection through the below experiments. Moreover, this paper uses numerical analysis about carrier transport layer thickness change on the basis of these experimental results that agree with simulation results.

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.2_2
• /
• pp.285-291
• /
• 2023

In this paper, in order to secure the safety and productivity of pine cone harvest, modeling and structural analysis of the hammering system for pine cone harvest drone that can easily access pine cone of Pinus koraiensis and collide with them to harvest them was performed. It calculate the equivalent stress for the structure of the hammering system and the yield strength of the applied material by applying the shear force of the stalk at which the pine cone is separated from the branch, and it is to verify the safety of the structure and propose an optimal design through appropriate factor of safety and design change. The shear force of the stalk at which the pine cone was separated from the branch was 468 N, and was applied to both ends of the hammering system. The yield strength of SS400 steel used in the hammering system is 245 ㎫, and the design change and structural analysis were performed so that the Von Mises stress could be less than 122.5 ㎫ by applying the factor of safety of 2.0 or more. As a result of the structural analysis of the frist modeling, the Von Mises stress was 220.3 ㎫, the factor of safety was 1.12, and the stress was concentrated in the screw fastening holes. As a result of the design change of the screw fastening holes, the Von Mises stress was 169.4 ㎫, the factor of safety was 1.45, and the stress was concentrated on the side part. As a result of the design change by changing screw fastening holes and adding ribs, the Von Mises stress was 121.6 ㎫, and the factor of safety was 2.02. The safety of the hammering system was secured with an optimal design with little change in mass. There was no deformation or damage as a result of experimenting on pine cone harvest by manufacturing the hammering system with an optimal design.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.6
• /
• pp.491-498
• /
• 2016

Stress on plates may increase in the neighborhood the edges or the holes for rivets or bolts. Excessive stress concentration may lead to severe breakage of the plates. Thus, it is important to conduct optimization of arrangement of holes at the design stage. In this paper, accuracy of FEM analysis was examined for such stress concentration. By changing the hole size on a narrow plate, change of the stress concentration factor(K) was investigated. Additionally, the same experiment was conducted about series of multiple holes on plate to investigate interaction between the adjacent holes. Then, the FEM results were compared to the reference predictions respectively. Finally, a method by which simple stress concentrating situations can be optimized, will be suggested. This method was examined by FEM, and showed similar tendency with the expectation. Therefore, this method can be valuable when arranging the holes on a plate.