• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.185-192
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• 2015

Expansion joint is the essential element of the bridge in many cases. When the bridge faces chloride of preventing freezing on the surface of the bridge, the expansion joints is damaged significantly, thus this reduces service life and increases maintenance cost of the bridge. As a solution of this problem, new technology using high ductile materials for the joint without expansion joint was developed and in this research, crack control performance, preventing leaking after the cracking, and chloride resistance were experimentally evaluated. As a result of the experiment, with PCM and FRC materials, the connecting joint suffered poor crack dispersion and severe damage by the chloride penetration while with high-ductile material, the connecting joint dispersed the tensile deformation to microcracks stably up to 7.5mm. Furthermore, under the sever conditions, the leaking was prevented and penetration of chloride ions was prevented after the crack occurred.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.6
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• pp.343-349
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• 2022

This paper proposes a new topology optimization scheme to determine optimized joints for multi-component models. The joints are modeled as zero-length high-stiffness spring elements. The spring joints are considered as mesh-independent springs based on a joint-element interpolation scheme. This enables the changing of the location of the joints regardless of the connected nodes during optimization. Because the joints are movable, the locations of the optimized joints should be aggregated at several points. In this paper, the novel joint dispersal (JD) constraint to prevent joint clustering is proposed. With the joint dispersal constraint, it is possible to determine the optimized joint location as well as optimized topologies while maintaining the minimum distance between each joint. The mechanical compliance value is considered as the objective function. Several topology optimization examples are solved to demonstrate the effect of the joint dispersal constraint.

• Journal of the Korean GEO-environmental Society
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• v.22 no.3
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• pp.31-35
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• 2021

The expansion joints installed on the bridge for the accommodation of expansion and contraction of the supper structure are essential members of the bridge. However, the expansion joints are deteriorated over time and the waterproof function weakens, causing rainwater to penetrate and deteriorate the structure. In order to solve the traffic congestion caused by frequent replacement of the old expansion joints along with the deterioration of the structure, a post-integrated abutment bridge in which the existing expansion joints are removed and replaced with reinforced concrete link connection has been applied to highway bridges since 2016. After the post-integrated abutment method was applied, it was partially applied to bridges in which the superstructure and abutment were jammed. In this study, the causes of problems that may occur when the post-integrated abutment method is applied to the jammed bridge were analyzed numerically. It was analyzed that damage occurred in the link connection part. Based on the results of this study, the application condition for the post-integrated abutment method is reinforced as it is not possible to apply the post-integrated abutment method to bridges are already jammed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.83-83
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• 2004

이 연구의 목적은 IT 기술을 사용하여 가상으로 기구 설계를 할 수 있는 소프트웨어를 개발하여 설계자들이 많은 시행착오를 줄이고 변경된 설계를 좀더 라르고 편리하게 설계에 적용할 수 있게 하는 것이다. 로봇 링크 설계시, 파라메트릭 기능이란 여러 개의 링크와 여러 개의 조인트로 연결된 기구에서 한 링크의 길이 또는 한 조인트의 각도를 변경시켰을 때, 그 링크 또는 조인트 뒤에 연결된 모든 링크들과 조인트들의 위치가 동시에 자동으로 변경되게 하는 기능을 말한다.(중략)

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.613-615
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• 1999

현실감이 있는 다관절체 물체의 동작을 만들기 위해 물리기반 모델링이 점차 많이 쓰여지고 있다. 이 방법에서는 충돌을 처리해 주어야 하는데, impulse를 이용하는 방법은 힘을 이용하는 방법보다 빠르기 때문에, 충돌반응에 많이 쓰여진다. 다관절체에 대한 impulse는 각각의 조인트들의 성질에 따라서 다르게 처리되어야 한다. 본 논문에서는 충돌반응을 위한 다양한 조인트들의 처리방법을 제시하고, 신속하게 처리할 수 있는 방법을 제시한다. 이를 이용하면, 복잡하게 연결된 물체들이라도 조인트를 서로 조합하여 충돌반응이 가능하다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.5
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• pp.187-193
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• 2006

A new jointing method using steel cramps with a unique configuration was developed for the field joint of precast deck slabs of highway bridges. In this jointing method, the looped distribution bars are connected by the cramps to the main reinforcements. Therefore, the joint can transfer the bending moment and shearing force through the interlocking effect caused by the cramps, and it is both excellent in installation on-site and economical compared with the loop joint currently in use. In order to confirm the bending and shear capacities and to clarify the failure mechanism of the joint, a series of static loading tests were carried out. From the results of these experimental studies, it was clarified that the cramp joint has enough load carrying capacity being equivalent to the loop joint.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06c
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• pp.437-439
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• 2011

본 논문에서는 카메라에서 입력되는 영상에서 객체의 특징 자동 추출하고 모바일 기기로 전송하여 인체의 움직임을 표현하는 시스템을 제안한다. 제안시스템은 연속된 입력영상에서 인체의 실루엣과 조인트를 자동추출하고 조인트를 추적함으로 객체를 추적한다. 추출된 특징은 객체의 각 연결점의 위치정보로 사용되며 특징을 중심으로 블록매칭 알고리즘을 적용하여 특징의 위치정보를 추적하고 모바일기기로 정보를 전송한다. 모바일 기기에서는 전송된 조인트 정보를 이용하여 인체의 움직임을 재현한다. 제안방법을 실험 동영상에 적용한 결과 인체의 실루엣과 조인트를 자동 검출하며 추출된 조인트로 인체의 매핑이 효율적으로 이루어졌다. 또한 조인트의 추적이 매핑된 인체에 반영되어 인체의 움직임도 적절히 표현되었다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.2
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• pp.108-114
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• 2002

In this paper, nonlinear finite element analysis is performed to ensure structural safety and to suggest the design improvement of wing-to-fuselage joint of the KSR-III rocket. In the joint, wings are attached to fuselage by fitting wing attachment part into the groove on the fuselage frame, and load transfer between wing and fuselage frame is accomplished mainly throug the contact of two members as well as fastening bolts. The careful finite element modeling has been proposed for the purpose of analyzing problems with relatively complicated load path. The detailed bolt modeling is conducted and GAP elemets are used to simulate contact problem between joined members and bolts. The suggested design improvement is verified by structural testing and the analysis results are compared with test results.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.119-129
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• 2015

Due to reduced self weight and alleviated wind effect, the multi-column wind towers that consist of a number of circular tubes as vertical members interconnected with horizontal brace members can be a substitute for the large-scale single cylinder wind towers. It is critical to guarantee strengths of tubular joints where vertical and horizontal members are structurally connected in order to make the whole multi-column system behave as a single tower structure. In this study, strength evaluation has been conducted for T-type tubular joints that are applicable in multi-column towers. Four of available design codes, i.e., AISC, Eurocode3, ISO 19902, CIDECT have been investigated and predictor equations in the considered design codes were validated and discussed through parametric numerical study on slenderness ratios of chords and braces at joints.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.91-99
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• 2024

Piping systems are crucial facilities used in various industries, particularly in areas related to daily life and safety. Piping systems are fixed to the main structures of buildings and facilities but do not support external loads and serve as non-structural elements performing specific functions. Piping systems are affected by relative displacements owing to phase differences arising from different behaviors between two support points under seismic loads; this can cause damage owing to the displacement-dominant cyclic behavior. Fittings and joints in piping systems are representative elements that are vulnerable to seismic loads. To evaluate the seismic performance and limit states of fittings and joints in piping systems, a high-stroke actuator is required to simulate relative displacements. However, this is challenging because only few facilities can conduct these experiments. Therefore, element-level experiments are required to evaluate the seismic performance and limit states of piping systems connected by fittings and joints. This study proposed a method to evaluate the seismic performance of an elbow specimen that includes fittings and joints that are vulnerable to seismic loads in vertical piping systems. The elbow specimen was created by connecting straight pipes to both ends of a 90° pipe elbow using flexible groove joints. The seismic performance of the elbow specimen was evaluated using a cyclic loading protocol based on deformation angles. To determine the margin of the evaluated seismic performance, the limit states were assessed by applying cyclic loading with a constant amplitude.