• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1355-1356
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• 2013

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.326-331
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• 2005

In this study, bearing response in single lap riveted joint is investigated by menas of single lap shear specimens with different types of adherend and fastener. Single lap shear specimen consists of adherend of SUS403 and carbon fabric/epoxy composite. Rivet of Avdel 2691 with 9.6mm diameter is used. Two types of fastener in single lap riveted joint are considered. One is a single lap shear specimen with single fastener, and the other is a single lap shear specimen with double fasteners. Especially, in case of single lap shear specimen with single fastener, the width of the specimen is varied as 2D, 3D, 4D, 6D at a fixed edge distance of 3D. Also the edge distance of the specimen is varied as 1.0D, 1.5D, 2.0D, 2.5D, 3.0D at a fixed width of 4D. In case of single lap shear specimen with double fasteners, two types of specimen are considered. One is a specimen with the width of 6D and edge distance of 3D. The other is a specimen with the width of 4D and edge distance of 2D. Here D designates the hole diameter for riveted joint.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1659-1670
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• 2001

It has been reported that cracks at mechanical fastener holes usually nucleate as elliptical corner cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks after penetrating the opposite surface. The weight function method is an efficient technique to calculate the stress intensity factors fur elliptical cracks using uncracked stress field. In this study the weight function method for three dimensional mixed-mode problem applied to elliptical comer cracks Is modified for elliptical arc through cracks and the stress intensity factors at two surface points of elliptical arc through cracks at mechanical fastener holes are analyzed by the weight function method. This study consists of two parts and in part I , the weight function method for elliptical arc through cracks is developed and verified.

• 대한기계학회논문집A
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• 제25권10호
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• pp.1671-1677
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• 2001

Cracks at mechanical fastener holes usually nucleate as elliptical comer cracks at the faying surface of the mechanical joints and grow as elliptical arc through cracks. The weight function method for elliptical arc through cracks at mechanical fastener holes has been developed and verified in the part I of this study. In part H, applying the weight function method, the effects of the amount of clearance on the mixed-mode stress intensity (actors are investigated and the change of crack shape is predicted from the analysis for various crack shapes. The stress intensity factors leer inclined crack are analyzed and critical angle at which mode I stress intensity factor becomes maximum is determined.

• 한국정밀공학회지
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• 제23권5호
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• pp.149-154
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• 2006

The cold expansion method (CEM) is one of the widely used a method to improve the fatigue behavior of materials in aerospace industry. Such improvement is due to the compressive residual stress developed when a tapered mandrel goes through the fastener holes a little smaller than the mandrel. CEM is retarded of crack initiation due to the compressive residual stress developed on the hole surface. Many researchers are studied a finite element analysis of residual stress around fastener hole. But in case of real model, fastener hole has a clamping force after CE. Therefore, it is respected that residual stress distributions should be changed due to clamping forces. In this paper, it was performed finite element analysis of residual stress by clamping force after CE in the plate having adjacent holes. From this study, it has been found that compressive residual stress near the hole increases according to clamping force. Also, the more increase clamping force, the more increases compressive residual stress. However, tensile residual stress increase beyond clamping force area.

• 대한기계학회논문집A
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• 제30권9호
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• pp.1110-1115
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• 2006

Cold expansion of fastener holes has been successfully used for many years to impart beneficial compressive residual stresses. Beneficial compressive residual stress of fastener hole that has been cold expanded before is reduced by using of materials for a long time. As a result, fatigue life of material is reduced. So, compressive residual stresses of material have to regenerate by re-cold expansion method. In this paper, it was carried out a finite element analysis about variation of residual stress due to tensile stress and residual stress distribution that was regenerated by re-cold expansion method in the fastener hole. Here, a diversity tensile stress was used. Also, it was performed a finite element analysis according to cold expansion rate of re cold expansion in order to obtain a beneficial compressive residual stress.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1078-1083
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• 2008

In this paper, assessed are the stability of vehicle and track according to vertical support stiffness difference on the transition between conventional and zero-longitudinal resistance (ZLR) rail fastener on bridge. For this, the spring constants of rail fastener have been determined according to different load ranges - KTX load (with or without impact factor) and test load of EN standards - from results of laboratory test on rail pad, the stability analysis of vehicle and track has been performed according to numbers or installation length of ZLR fasteners using vertical vehicle-track coupled model to consider train-track interaction. The analysis results reveal that only the wheel load variation slightly exceed the limit value when 2 ZLR fasteners are used with spring constant determined within the EN test load range, but, in all other cases, all evaluation items are satisfied. Thus, it can be said that the stability of vehicle and track will not be degraded by ZLR fastener.

• 대한토목학회논문집
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• 제26권4A호
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• pp.719-726
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• 2006

전세계적으로 널리 사용되고 있는 장대레일 궤도는 유지 보수 비용을 절감시키고, 궤도구성요소들의 수명이 길어진다는 장점을 가지고 있다. 그러나, 혹서기에 레일의 높은 온도 상승으로 인해 장대레일 궤도에는 매우 큰 압축력이 작용하게 되고, 이는 장대레일 궤도의 장출(좌굴)을 발생시켜 열차의 탈선으로 인한 사고로 이어진다. 본 연구에서는 장대레일 궤도의 좌굴에 많은 영향을 주는 궤도의 구성요소들 중에서 레일의 단면적과 단면2차모멘트 그리고 체결구의 파손과 병진 및 회전방향의 강성이 장대레일 궤도의 좌굴에 미치는 민감도를 파악하였다.

• 한국항공우주학회지
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• 제41권12호
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• pp.959-966
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• 2013

이 논문에서는 설계정보가 없는 노후 항공기를 사용한 P-3CK 해상초계기 사업을 바탕으로, 끝단거리 부족 결함 수리를 위한 패스너 홀 구조특성 연구를 수행하였다. 이를 위해 끝단거리 결함이 많이 발생했던 낫셀 론저론 부분을 선택하고, 1.5, 1.8, 2.0배 끝단거리에 대한 정적 해석을 수행하여 보수적인 응력을 구하였다. 이 응력을 바탕으로 TWIST의 표준하중 스펙트럼을 적용하여 비행하중을 생성하고, 이 비행하중을 이용하여 균열성장 피로해석을 수행하였다. 이 결과를 통하여 P-3CK 사업 중 수리된 패스너 홀의 유효성을 평가하고 정비주기 및 기준을 설정하였다.

• 한국철도학회논문집
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• 제18권1호
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• pp.43-52
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• 2015

궤도의 유지보수비와 전력소모비의 합이 최소로 되는 최적 체결구의 강성을 평가하여 가급적 이 값을 갖도록 체결구를 제작 및 유지관리하는 것은 국내 콘크리트궤도의 부설이 급격하게 증가하는 시점에서 철도의 경제성 제고 차원에서 중요한 과제라 할 수 있다. 본 연구에서는 콘크리트궤도에서 궤도의 유지보수비와 차량운행에 따른 전력소모비의 합을 최소로 하는 최적 체결구 강성을 평가하는 방법을 제시한 후, 국내 고속철도 콘크리트궤도에 맞는 최적 체결구 강성을 평가하였다. 체결구 강성에 따른 궤도 유지보수비를 합리적으로 평가하기 위하여 콘크리트궤도에 적합한 체결구 강성에 따른 궤도손상모델을 제시하였으며, 궤도손상에 따른 궤도 유지보수비 상관관계를 도출하였다. 윤중 계산 시 고도화된 수치해석적 기법을 적용하여 각 궤도구성품의 거동특성이 반영될 수 있도록 함으로써 체결구 강성에 따른 윤중변동을 보다 정확하게 평가할 수 있도록 하였다.