• Title/Summary/Keyword: Front-loading

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Engineering Elastic-Plastic Fracture Analysis for Semi-Elliptical Surface Cracked Plates Under Combined Bending and Tension (복합하중을 받는 평판에 존재하는 반타원 표면균열의 공학적 탄소성 파괴해석법)

  • Shim, Do-Jun;Kim, Yun-Jae;Choi, Jae-Boong;Kim, Young-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.6
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    • pp.1127-1134
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    • 2002
  • The present paper provides an engineering J estimation equation for surface cracked plates under combined bending and tension. The proposed equation is based on the reference stress approach, and the most relevant normalising loads to define the reference stress for accurate J estimations are given for surface cracked plates under combined bending and tension. Comparisons with J results from extensive 3-D FE analyses, covering a wide range of crack geometry, plate geometry and loading combination, show overall good agreement not only at the deepest point but also at arbitrary points along the crack front. for pure tension, agreement between the estimated J and the FE results is excellent, even at the surface point. On the other hand, for pure bending and combined bending and tension, the estimated J values become less accurate for locations close to the surface point. Thus the results in this paper will be useful to assess short-term fracture or low cycle fatigue of surface defects in plates under combined bending and tension.

A Study on the Pre-printed Clause of the Bill of Lading (선하증권 인쇄약관에 관한 연구)

  • Park, Sae-Woon
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.49
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    • pp.359-378
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    • 2011
  • UCP600 Article 20 (a) (v) states that contents of terms and conditions of carriage will not be examined and Article 34 states that a bank assumes no liability or responsibility for the general or particular conditions stipulated in a document. From this perspective, banks may seem to have no obligation to examine the pre-printed clause of B/L. However, ICC decided that no opinion could be given in relation to the issues surrounding B/Ls that contain delivery clauses. Accordingly, it is agreed by previous cases and some scholars that banks may refuse the B/Ls that contain delivery clauses which are not present in other B/Ls of the same goods and transport routes. Also, ICC published ICC Decision in July 2010 regarding on board notation. In this decision, if a B/L indicates a place of receipt that is different from the port of loading and there is an indication of a means of pre-carriage, then a dated on board notation will be required indicating the name of the vessel and the port of loading. Therefore, banks may,, in some cases, need to scrutinize the pre-printed clauses especially appearing in the front page of B/Ls.

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The Study on Correlation and Transformation Matrix Development in terms of Loading Histories of Body and Chassis for CTBA Suspension (CTBA 샤시 부품과 마운팅부 차체 입력 하중과의 상관성 연구 및 변환행렬식 개발)

  • Ha, Dong-Hyun;Park, Soon-Cheol;Jung, Won-Wook
    • Journal of Applied Reliability
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    • v.12 no.2
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    • pp.79-90
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    • 2012
  • The torsion beam type of rear suspension has been adopted by most manufactures of small to medium front wheel drive passenger cars. Previous studies analyzed only the load characteristics of CTBA(the coupled torsion beam axle)'s components. This paper analyzed the results of measurement after measuring loads and displacements, angles when a car equipped with the coupled torsion beam axle is driving in various roads. The most important durability factors for CTBA part are the force and direction of rear CTBA trailing arm. If there are design changes, it was difficult to make a sensor and install each time for measuring the trailing arm forces. After analyzing the loading histories between body and chassis, we developed the transformation matrix that can be converted to mutual force. This paper also deals with the analysis of the force behavior through the analysis of the influence and correlation between the body and chassis parts of cars.

Fatigue Crack-Tip Stress Mapping Using Neutron Diffraction

  • Choi, Gyudong;Lee, Min-Ho;Huang, E-Wen;Woo, Wanchuck;Lee, Soo Yeol
    • Korean Journal of Materials Research
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    • v.25 no.12
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    • pp.690-693
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    • 2015
  • Fatigue crack growth experiments were carried out on a 304 L stainless steel compact-tension(CT) specimen under load control mode. Neutron diffraction was employed to quantitatively measure the residual strains/stresses and the evolution of stress fields in the vicinity of a propagating fatigue-crack tip. Three principal stress components (i.e. crack growth, crack opening, and through-thickness direction stresses) were examined in-situ under loading as a function of distance from the crack tip along the crack-propagation path. The stress/strain fields, measured both at the mid-thickness and near the surface of the CT specimen, were compared. The results show that much higher compressive residual stress fields developed in front of the crack tip near the surface than developed at the mid-thickness area. The change of the stresses ahead of the crack tip under loading is more significant at the mid-thickness area than it is near the surface.

Three-dimensional finite element modeling of a transverse top-down crack in asphalt concrete

  • Ayatollahi, Majid R.;Pirmohammad, Sadjad;Sedighiani, Karo
    • Computers and Concrete
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    • v.13 no.4
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    • pp.569-585
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    • 2014
  • In this paper, a four-layer road structure consisting of an edge transverse crack is simulated using three-dimensional finite element method in order to capture the influence of a single-axle wheel load on the crack propagation through the asphalt concrete layer. Different positions of the vehicular load relative to the cracked area are considered in the analyses. Linear elastic fracture mechanics (LEFM) is used for investigating the effect of the traffic load on the behavior of a crack propagating within the asphalt concrete. The results obtained show that the crack front experiences all three modes of deformation i.e., mode I, mode II and mode III, and the corresponding stress intensity factors are highly affected by the crack geometry and the vehicle position. The results also show that for many loading situations, the contribution of shear deformation (due to mode II and mode III loading) is considerable.

Finite element procedures for the numerical simulation of fatigue crack propagation under mixed mode loading

  • Alshoaibi, Abdulnaser M.
    • Structural Engineering and Mechanics
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    • v.35 no.3
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    • pp.283-299
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    • 2010
  • This paper addresses the numerical simulation of fatigue crack growth in arbitrary 2D geometries under constant amplitude loading by the using a new finite element software. The purpose of this software is on the determination of 2D crack paths and surfaces as well as on the evaluation of components Lifetimes as a part of the damage tolerant assessment. Throughout the simulation of fatigue crack propagation an automatic adaptive mesh is carried out in the vicinity of the crack front nodes and in the elements which represent the higher stresses distribution. The fatigue crack direction and the corresponding stress-intensity factors are estimated at each small crack increment by employing the displacement extrapolation technique under facilitation of singular crack tip elements. The propagation is modeled by successive linear extensions, which are determined by the stress intensity factors under linear elastic fracture mechanics (LEFM) assumption. The stress intensity factors range history must be recorded along the small crack increments. Upon completion of the stress intensity factors range history recording, fatigue crack propagation life of the examined specimen is predicted. A consistent transfer algorithm and a crack relaxation method are proposed and implemented for this purpose. Verification of the predicted fatigue life is validated with relevant experimental data and numerical results obtained by other researchers. The comparisons show that the program is capable of demonstrating the fatigue life prediction results as well as the fatigue crack path satisfactorily.

Influence on the Ground Reaction Force Parameters According to Wearing Positions of Backpacks During Stair Ascending and Descending (계단 오르기와 내리기 시 가방착용 위치가 지면반력 파라미터에 미치는 영향)

  • Hyun, Seung-Hyun;Ryew, Che-Cheong
    • Korean Journal of Applied Biomechanics
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    • v.25 no.1
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    • pp.85-94
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    • 2015
  • Purpose : The purpose of this study was to investigate the influence on the ground reaction force parameters according to wearing positions of backpack for during stair ascending and descending. Methods : Participants selected as subject were consisted of young female(n=10) and performed stairs walks(ascending and descending) with 2 types of wearing position(front of trunk[FT], rear of trunk[RT]). Passive(Fz 1) and active(Fz 2) forces of the vertical GRF were determined from time function and frequency domain. Also shear forces(Fx, Fy 1, Fy 2), dynamic postural stability index(MLSI, APSI, VSI, DPSI), loading rate and center of pressure (${\Delta}COPx$, ${\Delta}COPy$, COP area) were calculated from time function and frequency domain. Results : Fx, Fy 1, Fy 2, and Fz 1 in GRF didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher forces than that of stair ascending. Particularly, Fz 2 of stair ascending showed higher forces than that of stair descending(p<.001), RT types showed higher than that of FT types(p<.05). MLSI, APSI, VSI, and DPSI of stair descending showed the increased stability index than that of stair ascending(p<.05), MLSI of RT types showed the decreased stability index than that of FT types(p<.05). Loading rate didn't show significant differences statistically according to the wearing positions of backpack(p>.05), but stair descending showed higher loading rate than that of stair ascending(p<.001). Also, ${\Delta}COPx$ in stair descending showed the increased movement than that of stair ascending(p<.05). Conclusions : A backpack of 10 kg(10 kg(ratio of body weights $17.61{\pm}1.17%$) showed significantly change GRF parameters according to wearing positions during stair ascending and descending. If possible, we suggest that the dynamic stability, in case of stairs walking with a smaller weights can be further improved.

Lateral load sharing and response of piled raft foundation in cohesionless medium: An experimental approach

  • Dinesh Kumar Malviya;Manojit Samanta
    • Geomechanics and Engineering
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    • v.38 no.2
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    • pp.139-155
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    • 2024
  • The piled raft foundations are subjected to lateral loading under the action of wind and earthquake loads. Their bearing behavior and flexural responses under these loadings are of prime concern for researchers and practitioners. The insufficient experimental studies on piled rafts subjected to lateral loading lead to a limited understanding of this foundation system. Lateral load sharing between pile and raft in a laterally loaded piled raft is scarce in literature. In the present study, lateral load-displacement, load sharing, bending moment distribution, and raft inclinations of the piled raft foundations have been discussed through an instrumented scaled down model test in 1 g condition. The contribution of raft in a laterally loaded piled raft has been evaluated from the responses of pile group and piled raft foundations attributing a variety of influential system parameters such as pile spacing, slenderness ratio, group area ratio, and raft embedment. The study shows that the raft contributes 28-49% to the overall lateral capacity of the piled raft foundation. The results show that the front pile experiences 20-66% higher bending moments in comparison to the back pile under different conditions in the pile group and piled raft. The piles in the piled raft exhibit lower bending moments in the range of 45-50% as compared to piles in the pile group. The raft inclination in the piled raft is 30-70% less as compared to the pile group foundation. The lateral load-displacement and bending moment distribution in piles of the single pile, pile group, and piled raft has been presented to compare their bearing behavior and flexural responses subjected to lateral loading conditions. This study provides substantial technical aid for the understanding of piled rafts in onshore and offshore structures to withstand lateral loadings, such as those induced by wind and earthquake loads.

BRUSHLESS DC MOTOR FOR A DIRECT DRIVE WASHING MACHINE (직결식 세탁기용 BRUSHLESS DC MOTOR)

  • Lee, Jin-Won;Kim, Chang-Joon;Sung, Bu-Hyun;Won, Jong-Hwa;Yi, You-Shin
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.406-408
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    • 1996
  • This paper describes the BLDC motor which is applicated for a top front loading domestic washing machine. This motor is adopted direct drive washing machine without gear-belt-pulley system. Because gear box is removed, machine volume and noise are reduced. Moreover mechanical troubles in gear box are removed. Realization of variable speed region through of PWM control and high speed is able to efficient washing and spinning.

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Data Transition Research to Derive Shape Factor in Analyzing Factors -Centering on the body shape of males in twenties- (요인분석시 형태요인을 도출시키기 위한 자료 변환 연구 - 20대 남성 체형을 중심으로 -)

  • 석혜정;김인숙
    • Journal of the Korean Home Economics Association
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    • v.40 no.2
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    • pp.67-86
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    • 2002
  • The purpose of this research is to offer a method to derive the body shapes and pose factors with resets from analyzing factors by using the measurement values of human body. 297 male subjects in their twenties participated in this study. 54 anthropometric and 35 photographic measurements were taken from each subject. Data is the several typical items selected among items and you have to make an index value by using these typical items and convert it. The index has high correlation with each item, is easy to be measured and is to be used after selecting an important item in designing prototype. With results of analyzing reliability level by each item, correlation and items that factor loading is low, the item that the correlation is high is to be removed within the range that maintains the reliability level. Five factors of the front part and seven factors of the profile came to be derived from this kind of process.