• Journal of the Korean Geotechnical Society
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• v.20 no.9
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• pp.167-176
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• 2004

Underground structures will be affected by the additional surcharge loads such as traffic load et al. Terzaghi (1956) suggested the equation on the influences of surcharge loads in vertically backfilled spaces. In field, the shapes of backfill spaces are not always formed vertically. Then the Terzagi (1956) equation is not suitable to use because of boundary condition. This study suggests equation to calculate the stress in backfilled space caused by surcharge loads when the backfilled space is sloped symmetrically. The suggested equation is verified by carbon box test and numerical analysis. The experimental results show good agreement with the suggested equation but the numerical analysis result shows a little disagreement. The differences are estimated to be caused by the fact that ground made by carbon rod has become more dense and internal frction and wall friction has increased itself as surcharge load is added but that this increase can not be considered in the numerical analysis. The suggested equation shows good agreement with Terzaghi (1956) equation in case of sloped backfill ground. According to the results, it is considered that the suggested equation can be applied not only to sloped space but also to vertical space. Further investigation using full scale experiment is needed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1585-1591
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• 2008

Recently it is tried to use load control for maneuver moving object. MIN design method proposed to solve control problem of nonlinear system using load concept. Min design method shows direct method for finding control value on the load control model. In this paper, is shown load control value for problem of line of sight on missile guidance. The load control value keep given velocity of missile and angle of attack for tracking target.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.118-124
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• 2017

To investigate and analyze the cause of the failure of the connecting rod bolt and the crank pin bearing bolt of the diesel engine of this study, the following results were obtained through site surveying, the investigation of literature referring to similar failures, testing and inspection of the fracture surface, and the experience of the researchers. The fractured crank pin bearing bolt of the diesel engine is estimated to be damaged later than the connecting rod bolt. From the shape of fracture surface, it is evident that the failed connecting rod bolt is fractured by fatigue failure due to abnormally repeated loads (e.g. loosening of the connecting bolt, etc.), and is not failed by brittle fractures due to the impact load. The surface of the U-nut on the fractured connecting rod bolt has been worsening due to the improper use of lubricant (agent for prevention of thread fixing) and no usage of separating the each connecting rod on each cylinder. Moreover, there is the possibility that those poor surface conditions of the fractured connecting rod bolt have affected the failure of the connecting rod bolt of the main engine. And it could be assumed that the mechanical characteristic and manufacturing process of the failed connecting rod bolt and crank pin bearing bolt, which were made by a domestic company, conform to the design requirements for those bolts.

• Tribology and Lubricants
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• v.1 no.1
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• pp.30-37
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• 1985

동수압적 미끄럼베어링의 작동원리는, 두개의 서로 경사진 면이 윤활제를 그 사이에 두고 상대적인 운동을 함에 있어서 두면사이에는 윤활유 막이 형성되어 압력이 형성되고 두면에 작용하는 하중의 지지하게 되므로 직접적 마찰없이 상대적 미끄럼운동을 한다는 것이다. 동수압적 유체윤활은 윤활틈새 내의 윤활유동에 동수압적 점성유체역학 이론을 적용하며 베어링윤활유막의 압력분포를 계산하기 위한 편미분 방정식의 발견이 그 근본을 이루고 있고, 미끄럼베어링에 대한 기본적연구는 1900년 이래로 계속 수행되고 있다. 크랭크샤프트와 피스톤 연결봉 사이의 베어링은 동하중을 크게 받으며 회전하므로 저어널과 축의 상대운동은 회전운동과 윤활면의 수직운동으로 나누어 해석할 수 있다.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.7 no.3
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• pp.411-419
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• 2017

Stress concentration is one of the causes of the damage due to the large stress than the mean stress acting on the bar. This paper presents the results for stress of a stepped bar with a hole under torsional loading. The analysis for stress concentration and shearing stress was done by ANSYS Workbench which is a commercial finite element analysis software. The analysis results on fillet and hole are increased as the distance between them are become close. In addition, the distribution of the maximum equivalent stress developed in the fillet and hole in the outside range of the specific distance L (-100 mm ~ 300 mm) was almost constant in the models used in the analysis. On the other hand, the distribution of the maximum equivalent stress developed in the fillet and hole in the inside range of the specific distance L (-100 mm ~ 300 mm) was rapidly increasing and decreasing the change in the models used in the analysis. In addition, it was also possible to identify the location where the differences between equivalent stresses of hole and fillet occurred within a specific distance L (-100 mm ~ 300 mm). The analysis results of paper can used when selecting a hole location in a stepped bar under torsional loading.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.21-30
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• 2013

LB-Deck is one of the widely used member in interior part of girders as a permanent formwork in structures, but it is not easy to apply to the exterior part of girder due to the overturning and excessive deflection. Considering allowable deflection and safety of the exterior part, Precast Concrete Cantilever Deck (PCC-Deck) is proposed with normal LB-Deck in inner part and extended bars of LB-Deck in outer part. Both numerical analyses and experimental tests were compared to check the safety and allowable deflection for 6 types of PCC-Deck, and D-type (with 16 mm top bar, 6 mm lattice bar, 12 mm bottom bar) is suggested as an optimal structural reinforcement to the 28 kN of maximum load and 27.49 mm of final deflection. The load resisting ratio of D-type under working load of 10 kN was about 2.8 times and 77.5% of improvement was observed.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.225-234
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• 2008

This study was carried out to select proper loading speed for deformation strength ($S_D$) of asphalt mixtures. Kim test using loading head of diameter(40mm) with radius(10mm) was conducted to measure $S_D$ in different loading speed (10mm/min, 30mm/min, 50mm/min, 70mm/min) and wheel tracking test was also conducted. The regression analyses between the So values and WT results were carried out by loading speeds. Higher $S_D$ was observed as increasing loading speed. This means that loading speed is a high influencing factor on $S_D$. The loading speed of 30mm/min was found as an optimum for better correlation with WT results than any other speeds from the regression analysis between $S_D$ and wheel tracking test results. $S_D$ value measured at other loading speed than 30mm/min has to apply the conversion coefficients.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.4
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• pp.129-137
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• 2007

An algorithm is proposed for estimating axle loads of trucks moving over a bridge by measuring dynamic responses. The bridge was modeled by a beam structure in the current applications of the proposed algorithm. Among the state vectors, measured acceleration was used and displacement was computed from measured strain at the same location. Nodal force vectors were computed by using a ready-made database of equivalent nodal force transformation matrix. The algorithm was examined through simulation studies and laboratory experiments. The effects of measurement noise and velocity error were investigated through simulation studies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.87-94
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• 2006

Estimating moving vehicle loads is important in modeling design loads for bridge design and construction. The paper proposes a moving force identification algorithm using moment influence lines measured at multi-axes. Density estimation function was applied to estimate more than two wheel loads when estimated load values fluctuated severely. The algorithm has been examined through simulation studies on a simple-span plate-girder bridge. Influences of measurement noise and error in velocity on the identification results were investigated in the simulation study. Also, laboratory experiments were carried out to examine the algorithm. The load identification capability was dependent on the type and speed of moving loads, but the developed algorithm could identify loads within 10% error in maximum.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.143.2-143.2
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• 2005