• Steel and Composite Structures
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• 제39권3호
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• pp.261-274
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• 2021

In a railway bridge, the CRTS II slab ballastless track is subjected to interlayer connection failures, such as void under slab, mortar debonding, and fastener fracture. This study investigates the influences of interlayer connection failure on the safe operation of high-speed trains. First, a train-track-bridge coupled vibration model and a bridge-track deformation model are established to study the running safety of a train passing a deformed bridge with interlayer connection failure. For each type of the interlayer connection failure, the effects of the failure locations and ranges on the track irregularity are studied using the deformation model. Under additional bridge deformation, the effects of interlayer connection failure on the dynamic responses of the train are investigated by using the track irregularity as the excitation to the vibration model. Finally, parametric studies are conducted to determine the thresholds of additional bridge deformations considering interlayer connection failure. Results show that the interlayer connection failure significantly affects the running safety of high-speed train and must be considered in determining the safety thresholds of additional bridge deformation in the asset management of high-speed railway bridges.

• 대한치과의사협회지
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• 제44권11호통권450호
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• pp.739-747
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• 2006

Objectives. The standardization of connection between fixture and abutment has not been defined. The success of dental implants was not always depends on connection. However, the connection mechanism is one of the most important things for dental implant treatment success. Most implant systems are very comparable in their design and engineering. They share many common characteristics and have similar strengths and weaknesses. Their significant weaknesses are connection, microgap and the resulting micromovement allowing bacterial contamination and bone loss. In the present study, we investigated the clinical performance of Ankylos implant (conical connection implant) Patients and Methods. The clinical performance of conical connection implant was studied under well-controlled clinical conditions. A total of 133 conical connection implants were placed in 50 patients from April 2005 to March 2006. The mean follow-up loading period of implants which was considered successful was 220$\pm$29 days. We recorded the age, sex, installation site, reason of edentulous region, bone density of installation site, diameter and length of dental implants and periods from installation to uncovering surgery using patients medical chart. Results Four Ankylos implants were lost during pre-loading period. 129 implants provided excellent clinical performance during 220$\pm$29 days on an average. The short-term success rate of this conical connection implant system was 96.99%.

• Structural Engineering and Mechanics
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• 제88권5호
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• pp.501-519
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• 2023

This paper introduces a new hybrid structural connection joint that combines shear walls with section steel beams, fundamentally resolving the construction complexity issue of requiring pre-embedded connectors in the connection between shear walls and steel beams. Initially, a quasi-static loading scheme with load-deformation dual control was employed to conduct low-cycle repeated loading experiments on five new connection joints. Data was acquired using displacement and strain gauges to compare the energy dissipation coefficients of each specimen. The destruction process of the new connection joints was meticulously observed and recorded, delineating it into three stages. Hysteresis curves and skeleton curves of the joint specimens were plotted based on experimental results, summarizing the energy dissipation performance of the joints. It's noteworthy that the addition of shear walls led to an approximate 17% increase in the energy dissipation coefficient. The energy dissipation coefficients of dog-bone-shaped connection joints with shear walls and cover plates reached 2.043 and 2.059, respectively, exhibiting the most comprehensive hysteresis curves. Additionally, the impact of laminated steel plates covering composite concrete floors on the stiffness of semi-rigid joint ends under excessive stretching should not be disregarded. A comparison with finite element analysis results yielded an error of merely 2.2%, offering substantial evidence for the wide-ranging application prospects of this innovative joint in seismic performance.

• 대한수학교육학회지:학교수학
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• 제4권4호
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• pp.555-563
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• 2002

The purpose of this paper is to try formulating a working definition of connection of informal and formal mathematical knowledge. Many researchers have suggested that informal mathematical knowledge should be connected with school mathematics in the process of learning and teaching it. It is because informal mathematical knowledge might play a important role as a cognitive anchor for understanding school mathematics. To implement the connection of them we need to know what the connection means. In this paper, the connection between informal and formal mathematical knowledge refers to the making of relationship between common attributions involved with the two knowledge. To make it clear, it is discussed that informal knowledge consists of two properties of procedures and conceptions as well as formal mathematical knowledge does. Then, it is possible to make a connection of them. Now it is time to make contribution of our efforts to develop appropriate models to connect informal and formal mathematical knowledge.

• 대한치과의사협회지
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• 제54권3호
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• pp.184-190
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• 2016

The osseointegration of titanium implants has been examined over the past 50 years. Many implant systems have been introduced and have become popular to the implant dentistry. The designs of the connection between implant fixture and abutment are divided into external vs internal connection. From beginning, the $Br{\aa}nemark$ system was characterized by an external hexagon. Internal connection has been developed to reduce stress transferred to the bone. These differences may have impact on the clinical procedures and protocols, laboratory and components costs, and incidence of complications. Therefore, the clinician has to know the different biomechanical features and understand their implications to produce successful implant-supported prosthesis with an external or an internal connection system.

• 과학교육연구지
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• 제38권2호
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• pp.331-343
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• 2014

전지의 연결방법에 따른 전류의 특성에 대한 초등교사들의 오개념 유형과 그 일관성에 대하여 조사되었다. 초등교사들의 전지의 연결방법에 따른 전류의 특성에 대한 오개념은 3가지 유형으로 나타났다. 14명의 초등교사들을 대상으로 한 이 연구에서, 전지들의 직렬연결과 병렬연결시 전류의 특성을 연결하는 전지의 수에 초점을 맞추는 유형에는 2명의 초등교사가, 전지의 직렬연결에 대한 개념과 병렬연결에 대한 개념을 혼동하는 유형에는 8명의 초등교사가, 그리고 전지의 직렬연결과 병렬연결에 대한 개념을 저항의 직렬연결과 병렬연결에 대한 개념으로 혼동하는 유형에는 4명의 초등교사가 분포하였다. 초등교사들은 전지의 연결에 대한 학습개념이 적용되는 상황에서 뿐만 아니라 분화개념이 적용되어야 하는 상황에서도 그들의 오개념 유형을 일관성 있게 적용하고 있었다.

• Steel and Composite Structures
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• 제31권6호
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• pp.617-628
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• 2019

As an extremely destructive accident, progressive collapse is defined as the spread of an initial local failure from element to element, resulting eventually in the collapse of an entire structure or disproportionately large of it. To prevent the occurrence of it and evaluate the ability of structure resisting progressive collapse, the nonlinear static procedure is usually adopted in the whole structure design process, which considered dynamic effect by utilizing Dynamic Increase Factor (DIF). In current researches, the determining of DIF is performed in full-rigid frame, however, the performance of beam-column connection in the majority of existing frame structures is not full-rigid. In this study, based on the component method proposed by EC3 guideline, the expression of extended endplate connection performance is further derived, and the connection performance is taken into consideration when evaluated the performance of structure resisting progressive collapse by applying the revised plastic P-M hinge. The DIF for structures with extended endplate beam-column connection have been determined and compared with the DIF permitted in current GSA guideline, the necessity of considering connection stiffness in determining the DIF have been proved.

• Geomechanics and Engineering
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• 제29권6호
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• pp.683-696
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• 2022

Dams are inevitably planned to be built on thick overburden with high permeability and deformability. The connection part between concrete cut-off wall in overburden and earth core in dam body is not only a key part of the anti-seepage system, but also a weak position. Large uneven settlement will be aroused at the concoction part. However, the interaction behavior and the scope of the connection part cannot be determined effectively. In this paper, numerical analysis of a high earth core dam built on thick overburden was carried out with large deformation FE method. The mechanical behavior of the connection part was detail studied. It can be drawn that there is little differences in dam integral deformation for different analysis method, but big differences were found at the connection part. The large deformation analysis method can reasonably describe the process that concrete wall penetrates into soil. The high plasticity clay has stronger ability to adapt to large uneven deformation which can reduce stress level, and stress state of concrete wall is also improved. The scope of high plasticity clay zone in the connection part can be determined according to stress level of soils and penetration depth of concrete wall.

• Steel and Composite Structures
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• 제47권3호
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• pp.375-382
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• 2023

The H-shaped steel beam is popular due to its ease of manufacturing and connection to the column. This profile, which is used as a shallow beam, needs the high weak-axis bending stiffness and torsional stiffness to meet the overall stability. Achieving the local beam flange stability, bearing capacity, bending stiffness, and torsional requirements need a great thickness and width of the beam flange, which causes, which will cause more uneconomical structural design. So, the box-section beam is the ideal alternative. However, the current design specifications do not have design rules for the bolt-and-welded connection of the box-section beam and box-section column. The paper proposes a novel bolt-and-welded connection of the box-section beams and box-section columns based on a high-rise structural design scheme. Three connection models, BASE, WBF, and RBS, are analyzed under cyclic loading in ABAQUS software. The failure modes, hysteresis response, bearing capacity, ductility, plastic rotation angle, energy dissipation, and stiffness degradation of all models are determined and compared. Compared with the other two models, the model WBF exhibited excellent seismic performance, ductility, and plastic rotation ability. Finally, model WBF was chosen as the connection scheme used in the project design.

• Steel and Composite Structures
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• 제51권5호
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• pp.487-498
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• 2024

Steel moment resisting frames (MRFs) typically have inter-story drift concentrations at lower stories during earthquakes as found from previous research. Hinged walls (HWs) can be used as structural strengthening components to force the MRFs deform uniformly along the building height. However, large moment demands are often observed on HWs and make the design of HWs non-economical. This paper proposes a method to reduce the moment demand on HWs using a ductile connection system between the MRFs and the HWs. The ductile connection system is designed with a yield strength and energy dissipation capacity, for the purpose of limiting the seismic forces transferred to the HWs and dissipating seismic energy. Nonlinear time history analyses were performed using 10 far-filed earthquakes at maximum considered earthquake level. The analysis results show that the proposed ductile connection system can reduce: (1) seismic moment demands in the HWs; (2) floor accelerations; (3) the connection force between HWs and MRFs.