• 한국공간구조학회논문집
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• 제3권1호
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• pp.87-97
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• 2003

The structural system that discreterized from continuous shells is frequently used to make a large space structures. As well these structures show the unstable phenomena when a load level over the limit load, and snap-through and bifurcation are most well known of it. For the collapse mechanism, rise-span ratio, element stiffness and load mode are main factor, which it give an effect to unstable behavior. In our real situation, most structures have semi-rigid joint that has middle characteristic between pin and rigid joint. So the knowledge of semi-rigid joint is very important problem of stable large space structure. And the instability phenemena of framed space structures show a strong non-linearity and very sensitive behavior according to the joint rigidity For this reason In this study, we are investigating to unstable problem of framed structure with semi-rigidity and to grasp the nonlinear instability behavior that make the fundamental collapse mechanism of the large space frame structures with semi-rigid joint, by proposed the numerical analysis method. Using the incremental stiffness matrix in chapter 2, we study instability of space structures.

• Tribology and Lubricants
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• 제16권1호
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• pp.39-45
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• 2000

In this paper, the effects of shaft and bearing flexibilities are investigated for the accurate modeling of a shaft-bearing system supported by ball bearings. Generally, rolling bearings are modeled by simple rigid pin-joint in the mechanical design. However, they can no longer be modeled by ideal boundary conditions in the advanced applications because the rigid pin-joint model cannot satisfy the current trends of mechanical design decreasing mass and reducing volume. Consequently the flexible support model of ball bearing is investigated using the static analysis module developed by A .B. Jones and T. A. Harris. A simple two-bearing system, supported by two deep groove ball bearings and radially loaded on the shaft midway between the bearings, is utilized to validate the coupled model of shaft-bearing system. Numerical computations using the model indicate that the shaft span length, locating/floating bearing arrangements and applied bearing size are significant factors in determining the mechanical behaviors. The flexible support model of ball bearing can be escaped to over-estimate in the bearing fatigue life. The proposed simple design formulation obtained by numerical simulations can approximately predict a rate of bearing life reduction as a function of shaft span length/shaft diameter (L/d).

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.14-15
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• 2018

Logistics facilities are characterized by wide spans and high flooring, most of which are constructed with PC (Precast Concrete) methods to meet a wide range of commercial and industrial needs. However, the PC structure is a pin joint design, and the construction cost is increased due to the restrictions caused by the installation process, and the construction period is lengthened. In order to solve the above problem, SMART Frame, which is a structural system similar to the steel frame structure, was developed by embedding a steel frame at both ends of the PC. The purpose of this study is to analyze the erection time reduction effect of steel connected precast concrete components (SMART frames) for long span and heavy loaded logistics buildings compared to existing PC frames. For this study, a logistics building constructed with pin joint PC components is selected as a case. The result is compared with the existing PC frame to confirm the erection time reduction effect.

• Journal of Welding and Joining
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• 제17권2호
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• pp.29-35
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• 1999

This study was intended to use for the fatigue test in real structures and offer basic data for optimum welding structure design. To this purpose, we obserded the effect of the size and distance of plug welding hole on the static strength and fatigue life of welding structure under the shear/bending load for the improvement of fatigue life of plug welding joint between S/MBR and C/MBR in the lower structure of large bus. The result below is shown through this study. 1) Static and fatigue strength are strongly influenced by the direction of plug weld hole distributed. 2) Distances and diameters of the distributed holes are little dependent on the static strengths 3) In case of the directions of the distributed plug weld holes are vertical to the loading pin, fatigue life is dependent on distance of the distributed hole. 4) In case of the directions of the distributed plug weld holes are parallel to the loading pin, fatigue life is dependent on distance of the hole diameter.

• Steel and Composite Structures
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• 제31권5호
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• pp.453-467
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• 2019

Portal frame structures, made up of cold-formed steel trusses, are increasingly being used for lightweight building construction. A novel pin-jointed moment connector, called the Howick Rivet Connector (HRC), was developed and tested previously in T-joints and truss assemblage to determine its reliable strength, stiffness and moment resisting capacity. This paper presents an experimental study on the HRC, in moment resisting cold-formed steel trusses. The connection method is devised where intersecting truss members are confined by a gusset connected by HRCs to create a rigid moment connection. In total, three large scale experiments were conducted to determine the elastic capacity and cyclic behaviour of the gusseted truss moment connection comprising HRC connectors. Theoretical failure loads were also calculated and compared against the experimental failure loads. Results show that the HRCs work effectively at carrying high shear loads between the members of the truss, enabling rigid behaviour to be developed and giving elastic behaviour without tilting up to a defined yield point. An extended gusset connection has been proposed to maximize the moment carrying capacity in a truss knee connection using the HRCs, in which they are aligned around the perimeter of the gusset to maximize the moment capacity and to increase the stability of the truss knee joint.

• 대한임베디드공학회논문지
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• 제17권4호
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• pp.191-197
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• 2022

This study proposes an image-based Pose Intention Network (PIN) algorithm for rehabilitation via patients' intentions. The purpose of the PIN algorithm is for enabling an active rehabilitation exercise, which is implemented by estimating the patient's motion and classifying the intention. Existing rehabilitation involves the inconvenience of attaching a sensor directly to the patient's skin. In addition, the rehabilitation device moves the patient, which is a passive rehabilitation method. Our algorithm consists of two steps. First, we estimate the user's joint position through the OpenPose algorithm, which is efficient in estimating 2D human pose in an image. Second, an intention classifier is constructed for classifying the motions into three categories, and a sequence of images including joint information is used as input. The intention network also learns correlations between joints and changes in joints over a short period of time, which can be easily used to determine the intention of the motion. To implement the proposed algorithm and conduct real-world experiments, we collected our own dataset, which is composed of videos of three classes. The network is trained using short segment clips of the video. Experimental results demonstrate that the proposed algorithm is effective for classifying intentions based on a short video clip.

• Journal of the Korean Wood Science and Technology
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• 제39권1호
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• pp.8-14
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• 2011

한국 전통 목구조양식에서 뼈대구조인 기둥-보 접합부를 이용하여 현대적인 기법을 적용한 목구조 접합을 개발하기 위하여 낙엽송 집성재를 구조부재로 사용하였다. 집성재를 이용한 전통 접합기술과 드리프트핀 접합으로 구성된 접합부의 부재는 공장에서 프리커트에 의해 가공하였다. 뼈대구조의 전체 성능을 파악하고 향상시키기 위한 기초 연구로서 핀접합부의 인발내력 시험과 각 접합부의 모멘트저항 시험을 행하였다. 본 연구에서 사용된 기둥-보 부재는 본 연구에서 사용된 주각부 및 보단부 접합철물로 이루어진 접합부에서 우수한 모멘트저항성능을 발휘하였다. 핀의 세장비에 따라 초기강성은 세장비가 클수록 다소 높게 나타났으며, 모멘트저항성능인 휨모멘트와 최대모멘트는 세장비가 작을수록 우수함을 알 수 있었다.

• Clinics in Shoulder and Elbow
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• 제9권2호
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• pp.189-195
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• 2006

Purpose: To analyze the result of the accurate open reduction of acromioclavicular (AC) joint and pin fixation, coracoclavicular (CC) screw fixation without CC ligament repair for AC joint injuries. Materials and Methods: Between January 2000 and December 2003, seventeen cases with at least one year follow-up among twenty-one cases underwent operation for AC-CC ligament injuries. A transverse incision approximately 5 cm in length was made over the clavicle, and the AC joint was reduced accurately. Under the image intensifier, a cannulated screw and washer were inserted for the CC ligament. Two Steinman pins were inserted for the AC joint and the AC ligament was repaired with nonabsorbable suture. Gentle passive range of motion was begun postoperative 2 weeks. The pins were removed at $6{\sim}8$ weeks and the screw was removed at $10{\sim}12$ weeks. The results were evaluated by a distance between AC and CC joints on plain films and ASES score at last follow-up. Results: At the last follow-up, there was no limitation of motion and average ASES score was 96($86{\sim}100$ points). There was no failure showing over 5 mm difference of distance compared to opposite side on the plain films. Seven cases had the skin damages and local infection due to pin migration and three cases showed the loosening of CC screw. Conclusion: We could have satisfactory results by accurate reduction of AC joint and simple pins and screw fixation for AC-CC ligament injuries.

• 한국항공우주학회지
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• 제41권12호
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• pp.967-974
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• 2013

저자는 최근 산업체 생산 현장에서 Z-피닝 복합재 구조물을 간편하게 제작할 수 있는 Z-피닝 패치 개념을 제안하였고, 이를 적용하여 복합재 단일-겹침 전단 접합시편을 제작하였으며, 정적시험을 통하여 54~68%의 접합강도의 향상을 발표하였다. 본 연구는 상기 연구의 후속으로서, 반복하중에 대한 접합강도의 향상을 측정하기 위하여 피로시험을 수행하였다. 사용된 Z-핀은 스테인레스강 핀이며, 복합재료와의 결합력을 증가시키기 위하여 표면을 요철 형상으로 가공하였으며, 화학적으로 부식시켰다. 반복하중 조건에서 접합강도는 약 98~125% 향상되었다.

• Journal of the Korean Wood Science and Technology
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• 제42권3호
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• pp.258-265
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• 2014

목구조물 접합부에 기존 드리프트핀(Drift pin)을 대체하고자 단판이나 합판을 유리섬유강화플라스틱(GFRP: Glass fiber reinforced plastic)과 복합 적층시킨 GFRP보강적층목재핀을 제작하였다. 더불어 GFRP보강적층목재핀을 사용하여 집성재 접합부의 인장형 전단내력 시험을 실시하였다. GFRP 배열에 따른 보강적층목재핀의 휨강도 시험결과 GFRP를 각층에 1장씩 삽입한 시험편(Type-A)이 가장 양호한 성능을 발휘하였다. 또한 압체압력 $1.96N/mm^2$, 온도 $150^{\circ}C$에서 한 시간 열압하여 고밀화한 시험편이 고밀화하지 않은 시험편과 비교하여 휨강도 성능이 1.57배 향상됨을 확인하였으며, 하중방향에 따라 Edgewise가 Flatwise보다 3.51배 높은 성능을 발휘하였다. 시험을 통해 가장 양호한 성능을 보인 Type-A 보강적층목재핀을 이용하여 전단내력 시험을 실시하였다. 접합구의 종류와 접합판의 종류를 달리하여 시험한 결과 드리프트핀과 강판을 적용한 시험체(Type-DS)와 비교하여 GFRP보강적층목재핀과 GFRP보강목재적층판을 적용한 시험체(Type-WL)가 1.12배 높은 전단내력이 측정되었으며 최대하중 이후에도 매우 양호한 인성이 관찰되었다.