• Title/Summary/Keyword: Load characteristics design

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A mathematical model for the along-wind coefficient of tower crane based on the member load

  • Wei Chen;Xianrong Qin;Zhigang Yang
    • Wind and Structures
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    • v.37 no.5
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    • pp.347-359
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    • 2023
  • The along-wind coefficient is the key parameter for wind load calculations in tower crane structure design. It is often calculated using overall parameter characteristics, which may lead to inaccurate results. In this study, six types of tower masts and four types of tower jibs with different overall structural characteristics and member characteristics are established. Through wind tunnel force tests and CFD numerical simulation, the along-wind coefficient of the overall structure and each member are obtained. Based on the characteristics of the slenderness ratio and spacing ratio of the members, a mathematical model for calculating the along-wind coefficient of the tower crane structure is proposed. The calculated results are in accordance with the wind tunnel test results. The maximum relative error is -6.25%, and the minimum relative error is 0.68%. To ensure accuracy, it is necessary to calculate the along-wind coefficient of the tower crane structure based on the load of each structure member rather than using overall parameter characteristics.

Load Transfer Characteristics on Drilled Shafts by Hole Stability Fluids (공벽유지용 유체에 따른 대구경 현장타설말뚝의 하중전이특성)

  • Lim, Dae-Sung;Park, Seong-Wan;Park, Jung-Hwan;Oy, Se-Hun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1100-1105
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    • 2008
  • In most drilled shafts construction sites, it is common, depending on the site condition, to use either water or slurry as fluids for maintaining stability of the holes, however, there are yet no design manuals by hole stability fluids. In this paper, in order to evaluate load transfer characteristics of the drilled shafts by hole stability fluids, two test piles are constructed over the soft ground of the lower Busan Bay based on the Bi-directional Pile Load Test. The test results showed that no ultimate states has found under the condition of applied loads with fresh water and slurry as hole fluids for drilled shafts. Then, the load transfer behavior were estimated with the data measured in fields and the effect of hole stability fluids were compared. All these results are presented in the paper.

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Experimental Study of Driving Load Conditions for the Wheel Bearing Hub Unit of Passenger Car (승용차용 Wheel Bearing Hub Unit 설계를 위한 주행 하중조건의 실험적 연구)

  • 김기훈;유영면;임종순
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.166-173
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    • 2002
  • The wheel bearing hub unit is developed type of wheel bearing unified with the hub parts. It has advantage of reducing the weight and the number of components. And, it also improves uniformity of manufacturing quality, In order to design the wheel bearing hub units, many techniques are used such as load analysis, structure analysis and bearing characteristics analysis and so forth. These techniques need highly accurate load conditions founded on service conditions. In this study, to design the wheel bearing hub units used widespread in passenger cars, the service load was measured through driving tests on the public roads and in the special events. The public roads are classified into highway, intercity road, rural road, urban road, and unpaved road so as to know what the characteristics of the road loads are. The results of the tests showed that the wheel force was relative to the lateral acceleration, and also could be calculated from the lateral acceleration. The lateral acceleration was measured from 0.0G to 0.6G in general driving on the public roads, with different distributions in each road type. In special events, the maximum lateral acceleration was measured from 0.8G to 1.3G.

A Study on Friction Characteristics of Motorcycle Disk Brake Using Design of Experiment (실험계획법을 이용한 이륜자동차 브레이크 디스크의 마찰특성에 관한 연구)

  • Jeun, Hwan-Young;Bae, Hwo-Jun;Park, Kyu-Jung;Ryu, Mi-Ra;Park, Heung-Sik
    • Tribology and Lubricants
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    • v.23 no.4
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    • pp.175-179
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    • 2007
  • The effect of manufacturing parameters on friction characteristics of motorcycle break system was studied using a design of experiment. Such parameters conditions have an effect on the frictional factor such as applied load, sliding speed, and number of ventilated disk hole. However, it is difficult to know the mutual relation of these factors. In this study, the friction characteristics using design of experiment containing 3 elements were investigated for an optimal condition for the best motorcycle break system employing full factorial design. From this study, the result was shown that the applied load in frictional factors was the most important, next to sliding speed, number of ventilated disk hole.

EFFECT OF MISALIGNMENT ON THE STATIC CHARACTERISTICS OF 3-LOBE proceeding BEARING

  • Strzelecki, S.;Radulski, W.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.95-96
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    • 2002
  • The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

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An Influence of Frictional Factors on the Friction Characteristics of Automobile Transmission Gear Materials by using Design of Experiment (실험계획법을 이용한 자동차 트랜스미션 기어용 소재의 마찰특성에 미치는 마찰인자의 영향)

  • Park Heung-sik;Bae Hyo-jun;Lee Sang-Jae;Lee Chan-kyu;Kim Young-Hee
    • Tribology and Lubricants
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    • v.21 no.2
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    • pp.93-99
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    • 2005
  • The fault of an automobile transmission gear occurs whenever moving tooth surfaces interact. Such a failure condition has an effect on the frictional factors such as applied load, sliding speed, frictional time and gear oil. However, it is difficult to know the mutual relation of these factors. In this study, the friction and wear tests were carried out to get the friction characteristics with carburized SCM420 and nitrocarburized NT100 have being used as automobile transmission gear materials. And it was undertaken to analyze the frictional factors that have effect on frictional characteristics by using design of experiment. From this study, the result showed that the applied load in frictional factors was the most important, next to frictional time, sliding speed. And the friction characteristics of nitrocarburized NT100 was more excellent than carburized SCM420.

Analysis of Transmission Load for Spur Gear Using Contact Theory (접촉 이론에 의한 스퍼 기어의 전달 하중 해석)

  • 독고욱;김형렬
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.1
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    • pp.198-206
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    • 2000
  • The transmission load of gear devices is important factor in the design of gear system. To design gear system precisely, an analysis and calculation methods for transmission load of gears are demanded. The purpose of this study is to develop a computer program for analyzing tooth load sharing of a spur gear system by means of the contact theory. In this paper, load transmission characteristics is identified with elastic contact problem which is assumed to quasi-static equilibrium. The modeling of spur gear tooth is accomplished by application of I-DEAS.

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Effect Analysis of Carrier Pinhole Position Error on the Load Sharing and Load Distribution of a Planet Gear (캐리어의 핀홀 위치 오차에 따른 유성기어의 하중 분할 및 하중 분포 영향 분석)

  • Kim, Jeong-Gil;Park, Young-Jun;Lee, Geun-Ho;Kim, Young-Joo;Oh, Joo-Young;Kim, Jae-Hoon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.5
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    • pp.66-72
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    • 2016
  • Gearboxes are mechanical components that transmit power by adjusting input and output speed and torque. Their design requirements include small size, light weight, and long lifespan. We have investigated the effects of carrier pinhole position error on the load sharing and load distribution characteristics of a planetary gear set with four planet gears. The simulation model for a simple planetary gear set was developed and verified by comparing analytical results with a putative model. Then, we derived the load sharing and load distribution characteristics under various pinhole position error conditions using the prototypical simulation model. The results showed that the mesh load factor and face load factor increased with the pinhole position error, which then influenced the safety factor for tooth bending strength and surface durability.

Dynamic performance prediction of a Supercritical oil firing boiler - Load Runback simulation in a 650MWe thermal power plant (초임계 오일 연소 보일러의 동특성 예측 연구 - 650MWe급 화력발전소의 Load Runback 모사)

  • Yang, Jongin;Kim, Jungrae
    • 한국연소학회:학술대회논문집
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    • 2014.11a
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    • pp.19-20
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    • 2014
  • Boiler design should be desinged to maximize thermal efficiency of the system under imposed load requirement and a boiler should be validated for transient operation. If a proper prediction is possible on the transient behavior and transient characteristics of a boiler, one may asses the performance of boiler component, control logics and operation procedures. In this work, dynamic modeling method of boiler is presented and dynamic simulation of load runback scenario was carried out on suprecritical oil-firing boiler.

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Characterization of Live Fire Load in Buildings - Heat Release Characteristics of Typical Live Fire Load in Bookstore - (건축물의 적재가연물 특성에 관한 연구 -대형서점의 적재가연물 연소발열성상-)

  • Nam, Dong-Gun;Yuji, Hasemi;Jung, Jong-Jin;Lim, Woo-Sub;SaKong, Seong-Ho
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2008.11a
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    • pp.3-6
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    • 2008
  • Heat release characteristics of live fire load are an important parameter for performance oriented fire safety design of a building. While investigations have been carried out on the fire load and its burning behavior in office, residential and commercial buildings and so on, little effort has been paid for the rational treatment of fire load in bookstore. In this report, burning behavior of typical combustible objects in bookstore are studied by measuring heat release rates of bookshelf with book.

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