• Journal of Welding and Joining
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• 제18권5호
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• pp.33-40
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• 2000

Fatigue crack propagation life of weld toe crack through residual stress field was estimated with Elber's crack concept. Propagation of weld toe crack is heavily influenced by residual stress caused by welding process, so it is essential to take into account the effect of residual stress on the propagation life of weld toe crack. Fatigue crack at transverse and longitudinal weld toe was studied respectively, which represent typical weld joint in ship structure. Numerical and experimental studies are performed for both cases. Residual stress near weldment was estimated through nonlinear thermo-elasto-plastic finite element method, and residual stress intensity factor with Glinka's weight function method. Effective stress intensity factor was calculated with Newman-Forman-de Koning-Henriksen equation which is based on Dugdale strip yield model in estimating crack closure level U at different stress ratio. Calculated crack propagation life coincided well with experimental results.

• 대한조선학회지
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• 제25권3호
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• pp.13-18
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• 1988

Three-dimensional turbulent flows over ship sterns are measured by using the hot-wire anemometer and static holes in the wind tunnel. A conventional stern and a barge-type stern are adopted for the present study. Three components of mean velocities, pressures on the hull and six components of Reynolds stresses are measured. Longitudinal velocity contours are more parallel to the hull surface and weak bilge vortices appear on the barges type stern rather than the conventional stern. Those viscous flow patterns may have close relations to improvements of the resistance and propulsion performance, which have been verified in the towing tests. Measured data files are valuable for the ensuing numerical studies.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.787-792
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• 2004

LRB(Lead rubber bearing) has small resistance force against slowly acting loadings such as temporal and creep loadings vice versa large resistance force against rapid loadings such as earthquake and braking loadings. By those mechanical characteristics, it has the advantage to reduce longitudinal load acting on abutments and piers, and moreover to in1prove the running stability of train by restricting the behavior of bridge under the required level. In this study, a stability evaluation method of CWR on the bridge with LRB is presented. Several parametric studies are carried to investigate how LRB contributes to the improvement of CWR stability.

• KCI Concrete Journal
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• 제14권2호
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• pp.69-75
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• 2002

This is the second of two part series on experimental studies of grout type transverse joints. In this paper, grout-type transverse joints between precast concrete slabs are tested to study the fatigue behavior. The tests are per-formed with loading equipment designed and constructed especially in the lab to introduce shear fatigue failures on the joints of the test specimens with repeated loads. Non-prestressed as well as prestressed specimens are selected based on static tests and these specimens are studied to identify the effect of prestress on the fatigue strength of the grout type joint. A comparison between prestressed and non-prestressed specimens indicates that longitudinal prestressing is an effective method to increase fatigue strength of the transverse joints. Based on the fatigue test, a rational estimation of the fatigue strength is proposed to aid design of the grout-type transverse joints.

• 콘크리트학회논문집
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• 제14권4호
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• pp.513-520
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• 2002

본 연구는 철근콘크리트 모멘트골조 기둥의 구조적인 성능을 평가하는 것이다. 이를 위하여 기존에 진행된 연구들의 실험결과를 모아 비교하였다. 본 연구에서 고려하는 실험변수는 소성힌지 부분에서 철근이음 유무, 종 방향 철근 비, 횡 방향 철근 비, 축력비이다. 또한, 본 연구에서는 시험체의 강도, 변위, 연성능력과 함께 소성힌지 길이를 비교하였다.

• 대한치과의사협회지
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• 제10권5호
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• pp.273-276
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• 1972

The original sample in this investigation included 36 children around the age of eight (mean age:8 year-lmonth) at the beginning. Study casts were obtained and measured every 6 months in two years of longitudinal study period in order to observe the changes of maxillary dental arch as well as the eruptional status of the maxillary lateral incisors. The results were as follows.: 1) The length of upper dental arch was increased gradually during the examination period. 2) The width between maxillary first molars was increased gradually during the examination period. 3) Intercanine distance in upper dental arch was increased gradually and the increment was conspicuous immediately after the eruption of maxillary lateral incisors.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2014년도 추계 학술논문 발표대회
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• pp.83-84
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• 2014

The whole wall system behaves as one section because single walls composing irregular wall are connected to each other. Although stress of a single wall is affected to the connected wall under lateral load, the stress is not transferred to whole sections and is concentrated on particular part of the wall as well. Therefore these walls can be divided into the effective and ineffective section. The purpose of this study is to compare design result of irregular wall using codes and previous studies on an effective width of the wall and to analyze reduction of the longitudinal bar of irregular wall.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.113-119
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• 1998

This study is focused on evaluation of the structural behavior of skewed bridge during earthquake. The variation of natural frequencies and the lateral forces at pier shoes by the skewness and the rotational effect about vertical axis of skewed bridge due to seismic activity are analytically evaluated and identified through case studies. For this purpose, the composite steel girder highway bridges are selected as case study models. The seismic analyses by response spectrum method and time history method are performed for the selected models. It has been recognized that the frequency of longitudinal model increased as the skew angle decreased, while the lateral mode frequency showed the opposite trends. When the skew angle decreased, longitudina seismic forces of the bridge at the pier were increased but decreased in transverse direction. And it also has been found that the skewed bridges of the case study models showed the rotational behavior about vertical axis due to motion of San Fernando earthquake at Pacoima Dam.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.1-27
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• 2015

This article presents a theoretical parametric analysis on the ultimate torsional behaviour of axially restrained reinforced concrete (RC) beams. This analysis is performed by using a computing procedure based on a modification of the Variable Angle Truss Model. This computing procedure was previously developed to account for the influence of the longitudinal compressive stress state due to the axial restraint conditions provided by the connections of the beams to other structural members. The presented parametric study aims to check the influence of some important variable studies, namely: torsional reinforcement ratio, compressive concrete strength and axial restraint level. From the results of this parametric study, nonlinear regression analyses are performed and some design charts are proposed. Such charts allow to correct the resistance torque of RC beams (rectangular sections with small height to width ratios) to account for the favorable influence of the axial restraint.

• Earthquakes and Structures
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• 제7권5호
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• pp.861-875
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• 2014

This paper studies the response of seismic behavior of reinforced concrete exterior beam-column joints under reversal loading with different anchorages and joint core details. The joint core was detailed without much confinement (group-I) and/or with proposed X-cross bars in the core (group-II). The beam longitudinal reinforcement's anchorages were designed as per ACI 352 (headed bars), ACI 318 (conventional $90^{\circ}$ bent hooks) and IS 456 ($90^{\circ}$ bent hooks with extended tails). The nonlinear finite element analysis response of the beam-column joints was studied, along with initial and progressive cracks up to failure. The experimental and analytical results were compared and presented in this paper to make more scientific conclusions.