• Title/Summary/Keyword: Hub space

Search Result 128, Processing Time 0.028 seconds

A Study on Structural Safety Analysis of Hub Space (허브스페이스의 구조적 안전성 해석에 대한 연구)

  • Han, Moonsik;Cho, Jaeung
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.23 no.3
    • /
    • pp.352-359
    • /
    • 2015
  • This study investigates the analysis result of structure and fatigue due to the models of the hub space with bolt joint at wheel and the existence or nonexistence of hub ring as the part of suspension system of vehicle. As the static analysis result, the structural vulnerability can be found at hub bolt and the center of wheel at three models. Model 2 and 3 have nearly same deformation and model 1 can be endured at the least load among three models. As the fatigue analysis result, fatigue lives of three models are same at the severest load of SAE bracket history. As many screw threads of weak bolts are jointed in case of model 1, model 1 is shown to be the weakest at fatigue damage among three models. By the result of this study, model 1 with bolt joint becomes most weakest among three models. As model 2 with no hub ring and model 3 with hub ring have the nearly same states of analysis results, hub ring is shown to have no influence on the safety of automotive driving.

Aerodynamic Drag Prediction of a Bearingless Rotor Hub (무베어링 로터 허브의 공기역학적 항력 예측)

  • Kang, Hee-Jung
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.40 no.8
    • /
    • pp.655-661
    • /
    • 2012
  • In this study, aerodynamic drag of a bearingless rotor hub was predicted by computational fluid dynamics methodology using unstructured overset mixed meshes. The calculated results showed that the drag due to pressure forces rather than the viscous drag act as a major factor on both the fuselage and rotor hub, and the drag acting on the torque tube accounted for the largest portion in the hub drag. It was also found the hub drag accounted for 39 ~ 41% of the fuselage drag. Finally, the result confirmed the drag of the designed rotor hub satisfied the requirement of the aerodynamic hub drag by comparing with the drag trend of developed helicopter.

Spiral Magnetic Field Lines in a Hub-Filament Structure, Monoceros R2

  • Hwang, Jihye;Kim, Jongsoo
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.45 no.1
    • /
    • pp.59.3-60
    • /
    • 2020
  • We present the results of polarization observations at submillimeter wavelengths towards Monoceros R2 (Mon R2). The polarized thermal dust emission was obtained from SCUBA-2/POL-2 at 450 ㎛ and 850 ㎛, simultaneously. This observation is a part of the JCMT BISTRO survey project. The polarization angle distributions at 450 ㎛ and 850 ㎛ are similar and the mean value of angle differences at two wavelengths is 5.5 degrees. The Mon R2 is one of massive star-forming regions containing a clear hub-filamentary structure. The hub region shows star formation activities, and surrounding filaments provide channels for matters to move into the hub region. It is not well known the role of magnetic fields in a hub-filamentary structure. Some studies have shown well-ordered polarization segments along a filamentary structure and magnetic field morphology traced by polarization segments is interpreted as to help gas flow along the filamentary structrue. Our observations shows that filaments in Mon R2 have spiral structure and the magnetic field lines are parallel to the filaments. We interpret that the spiral structure can be formed by a rotation hub-filament system with gas flowing along the filaments to the hub. We found several dust clumps at the central part of the hub region of the Mon R2. They seems to be formed at locations where spiral field lines meet each other. These results show one observational example that a magnetic field play a role in gas flow.

  • PDF

An Essay on the Possibility of New Seoul International Airport as a Regional Hub (신공항(新空港)의 허브공항화(空港化)에 관한 소고(小考))

  • Kim, Jong-Seok
    • The Korean Journal of Air & Space Law and Policy
    • /
    • v.5
    • /
    • pp.303-320
    • /
    • 1993
  • The construction of New Seoul International Airport is under way despite much controversy. Among much discussed, but not well-formulated controversy is the possibility of the airport as a hub in the North Asia Region. This paper specifies the factors which render it possible for an airport to be a regional hub. Then each factor is applied to the new airport to see whether it can function as a hub airport. Also examined is the qualitative cost and benefit calculation related to the hub function. The usual discussion has missed one big point of cost side of hub function in the belief that the hub only produces benefits to the national economy where the airline and airport industry belong; earlier-than-expected congestion and the necessity to expand the airport sufficiently enough to accommodate the increasing air demand. An airport as a hub is determined by several factors; geographical location ; economic status of the country where the airport belongs ; bilateral air service agreements according to which the airlines can exercise the route rights; the airport charges which directly influence the cost structure of the carriers ; international aviation and airport related policies of each country in the region ; airport capacity etc. The tentative implications of this paper are the followings; first, the new airport is able to function as a regional hub in the transpacific routes which connect Asian countries and North America. That is, directional hubbing by the airlines is implicated; second, the main benefits may be accrued to american airlines exercising all the route rights in the Asian region; third, the governmental effort to make the new airport a regional hub must take caution in optimizing the hubbing level (% of transitting passengers and freight) between the benefits and the costs. Further Studies may include optimal level of hubbing for the new airport and, quantification of the impact of the new airport on the national economy depending on the degree of hubbing.

  • PDF

Effects of Composite Couplings on Hub Loads of Hingeless Rotor Blade (무힌지 로터 블레이드의 허브하중에 대한 복합재료 연성거동 연구)

  • Lee, Ju-Young;Jung, Sung-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.32 no.7
    • /
    • pp.29-36
    • /
    • 2004
  • In this work, the effect of composite couplings on hub loads of a hingeless rotor in forward flight is investigated. The hingeless composite rotor blade is idealized as a laminated thin-walled box-beam. The nonclassical effects such as transverse shear, torsional warping are considered in the structural formulation. The nonlinear differential equations of motion are obtained by applying Hamilton's principle. The blade response and hub loads are calculated using a finite element formulation in space and time. The aerodynamic forces acting on the blade are calculated by quasi-steady strip theory. The theory includes the effects of reversed flow and compressibility. The magnitude of elastic couplings obtained by MSC/NASTRAN is compared with the classical pitch-flap $({\delta}3)$ or $pitch-lag({\alpha}1)$ coupling. It is found that the elastic couplings have a substantial effect on the behavior of $N_b/rev$ hub loads. Nearly 10 to 40% of hub loads is reduced by appropriately tailoring the fiber orientation angles in the laminae of the composite blade.

Vibratory Hub Loads of Helicopters due to Uncertainty of Composite Blade Properties (복합재료 블레이드의 불확실성을 고려한 헬리콥터 허브 진동하중 해석)

  • You, Young-Hyun;Jung, Sung-Nam
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.37 no.7
    • /
    • pp.634-641
    • /
    • 2009
  • In this work, the behavior of vibratory hub loads induced due to the uncertainties of composite material properties for each of the participating rotor blades is investigated. The random material properties of composites available from the existing experimental data are processed by using the Monte-Carlo simulation technique to obtain the stochastic distribution of sectional stiffnesses of composite blades. The coefficients of variation (standard deviation divided by the mean) obtained from the sectional stiffness constants are used as an input to the comprehensive aeroelastic analysis code that can evaluate the hub loads of a rotor system. It is found that the uncertainty effects of composite material properties inevitably bring a dissimilarity to the rotor system. The influence of hub vibration response with respect to the individual stiffness (flatwise bending, chordwise bending and torsion) changes is also identified.

A Case Study on Establishing U-Information HUB System At Incheon International Airport (인천국제공항공사의 U-Information Hub 시스템 구축에 관한 사례연구)

  • Lee, Dong Wook;Suh, Eun Jung
    • Journal of Korea Society of Digital Industry and Information Management
    • /
    • v.5 no.3
    • /
    • pp.201-213
    • /
    • 2009
  • An Airport is important space and even stands for the country because diverse people from other countries use a variety of facilities in the gateway to the country. Therefore, It is urgent for those people to increase efficiency and convenience of its usage. But we have a problem with process of passenger and this paper with the object of finding the solution in case study. This paper focus on information system, especially Intelligent Airport Information System to streamline process of passenger. There are a few of countries adopted this system in process. Therefore, IIAC(Incheon International Airport Corporation) establishing u-Information HUB System. It is unique and differential characteristics to Facilitation and increase passenger's satisfaction. u-Information HUB system unified stakeholder's process of Facilitation in Air Traffic Sides. u-Information HUB system gets the highest state of efficiency to Facilitation. This Paper is attempt to find new effort

CFD Analysis of CRW Unmanned Aerial Vehicle and Drag Reduction Strategy (CRW 무인 항공기의 공력 해석 및 항력 감소 방안)

  • Kim, Cheol-Wan;Chung, Jin-Deog
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.32 no.10
    • /
    • pp.20-27
    • /
    • 2004
  • In this study, CFD analysis for 2D ellipse and 3D CRW UAV are performed. Furthermore, flow analysis around a hub connecting body and rotor is analyzed and a strategy to reduce the drag caused by the hub is sought. Also, the idea of fairing installation is confirmed by a wind tunnel test.

Analysis of Driver's Field of View using a Shadow Algorithm (그림자 계산을 이용한 운전자의 시계성 해석)

  • 김재정;하용수;김용철
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.5 no.5
    • /
    • pp.123-131
    • /
    • 1997
  • To ensure drive's field of view, obstruction area generated by a steering wheel, hub and spoke must be considered at the early stage of automobile design. The current approach to computing obstruction area proposed by SAE is based on 2D drafting procedures so that it is not precise and errorprone. In the paper we discuss the novel approach which models the obstruction area as the shadows of the steering wheel, hub and spoke by assuming the human eye as light sources. The approach is based on ray tracing and space transformations for that it can be applied when free form curves are hired to represent the steering wheel, hub and spoke in CAD environment. As a result, it gives more predise and reliable results than SAE approach.

  • PDF

Aeroelastic Characteri stics of Rotor Blades with Trailing Edge Flaps

  • Lim, In-Gyu;Lee, In
    • International Journal of Aeronautical and Space Sciences
    • /
    • v.8 no.1
    • /
    • pp.115-121
    • /
    • 2007
  • The aeroelastic analysis of rotor blades with trailing edge flaps, focused on reducing vibration while minimizing control effort, are investigated using large deflection-type beam theory in forward flight. The rotor blade aerodynamic forces are calculated using two-dimensional quasi-steady strip theory. For the analysis of forward flight, the nonlinear periodic blade steady response is obtained by integrating the full finite element equation in time through a coupled trim procedure with a vehicle trim. The objective function, which includes vibratory hub loads and active flap control inputs, is minimized by an optimal control process. Numerical simulations are performed for the steady-state forward flight of various advance ratios. Also, numerical results of the steady blade and flap deflections, and the vibratory hub loads are presented for various advance ratios and are compared with the previously published analysis results obtained from modal analysis based on a moderate deflection-type beam theory.