• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1075-1084
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• 2014

It is necessary to construct an equipment catalog in plant design. A different level of detail may be needed for the three-dimensional (3D) computer aided design (CAD) data for equipment, depending on the purpose. Equipment suppliers provide CAD data with high complexity, whereas plant designers need CAD data with low complexity. Therefore, it is necessary to simplify the 3D CAD assembly data. To resolve this issue, a system for automatically simplifying the 3D CAD assembly data of equipment was developed. This paper presents the architecture of the system, the detailed functions of the system, and a neutral data format used for uploading simplified 3D CAD assembly data to a plant 3D CAD system. In addition, experiment results using the prototype system are explained.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.383-387
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• 2004

The Fuel Test Loop (FTL) consists of In-Pile Test Section (IPS) and Out-of-Pile System (OPS). The test condition in IPS such as pressure, temperature and quality of the main cooling water, can be controlled by the OPS. The FTL has been developed to be able to irradiate three pins to the core irradiation hole (IR1 hole) by considering for its utility and user's irradiation requirement. The IPS vessel assembly (IVA) consists of IPS head, outer pressure vessel, inner pressure vessel, inner assembly and test fuel carrier. The IVA is approximately 5.6 m long and fits within a 74 mm in diameter envelope over the full height of the chimney. Above the top of the chimney, the head of the IPS is enlarged to allow the closure flanges and pipe work connections. IVA was designed to test the CANDU and PWR nuclear fuel pin together. Specially, wished to minimize interference by nuclear fuel change in design and synthesize these items and shape design for IVA.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.22-34
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• 2020

Three-dimensional (3D) computer-aided design (CAD) models require different levels of detail (LODs) depending on their purpose. Therefore, it is beneficial to automatically simplify 3D CAD assembly models to meet the desired LOD. Feature-based 3D CAD assembly models typically have the lowest and highest feasible limits of LOD during simplification. In order to help users obtain a feasible simplification result, we propose a method to simplify feature-based 3D CAD assembly models by determining the lowest and highest limits of LOD. The proposed method is verified through experiments using a simplification prototype implemented as a plug-in type module on Siemens NX.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.6
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• pp.894-903
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• 2018

In the case of helicopters, the development of parts technology is rapidly changing, and the complexity is rapidly increasing. Particularly, the surge of various electric and electronic systems is recognized as a problem that is directly related to the safety of the helicopter. Due to these problems, there is a growing interest in reliability evaluation in the face of the problem of confirming and certifying the reliability of parts in the development stage. In this paper, the analysis of the failure mechanism of the wiper system was carried out, and the priority and importance of each failure mode were checked by using the results, and major stress factors were derived and the corresponding acceleration model was selected. Also, the accelerated lifetime test time was calculated according to the life test time, acceleration status and acceleration level of the steady state by using the selected acceleration model and characteristic values.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.688-693
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• 2007

Most frame structures cannot be manufactured in a single-piece form. Ideally, when a structure is built up by assembling multi pieces, assembly at the joints should be rigidly performed enough to have almost full stiffness, which is difficult for practical reasons such as manufacturing cost and time. In this research, we aim to develop a manufacturability-oriented compliance-minimizing topology optimization using a ground beam model incorporating additional zero-length elastic joint elements. In the present formulation, design variables control the stiffness of zero-length elastic joints, not the stiffness of beams. Because joint stiffness values at the converged state can be utilized to select candidate assembly locations and their strengths, the technique is extremely useful to design multi-piece frame structures. An optimal layout is also extracted based on the stiffness values.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.1-10
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• 2007

This paper presents a design guidance of jig/fixture for flexible manufacturing system based on the verification of a base assembly motion instability. In flexible assembly system, the base assembly needs to be maintained in its assembled state without being taken apart. This requires stability in motion while the base assembly is handled or tilted. Therefore, the instability of the base assembly motion should be considered when determining the guide line of designing jig/fixture by evaluating a degree of the motion instability of the base assembly. To derive the instability, first we inference collision free assembly directions by extracting separable directions for the mating parts and calculate the separability which gives informations as to how the parts can be easily separated. Using these results, we determine the instability evaluated by summing all the modified separabilities of each component part within base assembly.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.4
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• pp.317-326
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• 2022

This research performed single fiber pull-out test to evaluate the effect between fineness modulus of cement composites and the fiber bond performance (bond strength and pull-out energy). A synthetic fiber (polypropylene) and a steel fiber (hooked ends type) were inserted in the middle of dog bone shape specimens which were designed with fine aggregates of F. M. 1.96, 2.69, 3.43. The experiment results showed bond strength and pullout energy of synthetic fiber are improved as fineness modulus of cement composites increases. It is considered that the frictional resistance between synthetic fiber and cement composite increases as fineness modulus of cement composite increases and consume more energy while pull out the fiber from cement composite. However bond performance of steel fiber which resist pull out by mechanical behavior is less effected on fineness modulus of cement composite. It is considered that the mechanical fixedness of hooked ends exerts a greater effect on the pullout resistance than the frictional resistance between the cement composite and the steel fiber so F. M. of fine aggregate has a relatively small effect on the pullout resistance with the steel fiber.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.102.1-102.1
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• 2005

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.1
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• pp.215-222
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• 1993

A general method is proposed for stiffness analysis of the leaf springs only using the geometric data and Young's modulus of the leaf springs. In this method, an engineering beam theory and Castigliano's theory are applied for the derivation of the stiffness of the leaf springs. To show realiability and effectiveness of this method, the stiffness from the proposed method is compared with the results for various types of leaf springs. From these comparisons the proposed method has been proved to be effective and reliable to estimate the stiffness of the leaf springs.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.236-244
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• 2007

The 40% scaled vehicle of Smart UAV has been developed for the investigation of basic flight characteristics and the verification of flight control algorithm. The similar gimbal hub and drive train with the full scale UAV were implemented and a forced air cooling reciprocating engine was installed. The various kind of tests were conducted for the major components of the vehicle. The important performance and mechanical endurance of the fabricated vehicle were identified by ground and hovering test.