• Title/Summary/Keyword: inertia

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Development of Simulator for High-Speed Elevator System (고속 엘리베이터 시스템용 시뮬레이터 개발)

  • Ryu, Hyeong-Min;Kim, Seong-Jun;Seol, Seung-Gi;Gwon, Tae-Seok;Kim, Gi-Su;Sim, Yeong-Seok;Seok, Gi-Ryong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.2
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    • pp.77-82
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    • 2002
  • This Paper describes the dynamic load simulator for high-speed elevator system, which can emulate 3-mass system as well as equivalent 1-mass system. In order to implement the equivalent inertia of entire elevator system the conventional simulators have generally utilized the mechanical inertia(flywheel) with large radius, which makes the entire system large and heavy. In addition, the mechanical inertia should be replaced each time in order to est another elevator system. In this paper, the dynamic load simulation methods using electrical inertia are Presented so hat the volume and weight of simulator system are greatly reduced and the adjustment of inertia value can be achieved easily by software. Experimental results show the feasibility of this simulator system.

Moment of inertia of liquid in a tank

  • Lee, Gyeong Joong
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.1
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    • pp.132-150
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    • 2014
  • In this study, the inertial properties of fully filled liquid in a tank were studied based on the potential theory. The analytic solution was obtained for the rectangular tank, and the numerical solutions using Green's 2nd identity were obtained for other shapes. The inertia of liquid behaves like solid in recti-linear acceleration. But under rotational acceleration, the moment of inertia of liquid becomes small compared to that of solid. The shapes of tank investigated in this study were ellipse, rectangle, hexagon, and octagon with various aspect ratios. The numerical solutions were compared with analytic solution, and an ad hoc semi-analytical approximate formula is proposed herein and this formula gives very good predictions for the moment of inertia of the liquid in a tank of several different geometrical shapes. The results of this study will be useful in analyzing of the motion of LNG/LPG tanker, liquid cargo ship, and damaged ship.

Measurement of Inertia of Turbocharger Rotor in a Passenger Vehicle (승용차용 터보과급기 로터의 관성모멘트 측정)

  • Chung, Jin Eun;Lee, Sangwoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.24 no.1
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    • pp.33-38
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    • 2016
  • The turbocharger is an essential component to realize the engine down-sizing. The moment of inertia of turbocharger rotor is an important parameter with respect to acceleration performance of the vehicle. It can be calculated from the CAD software based the geometry data and the material properties. But the accurate value of the inertia of turbocharger rotor must be measured through the experimental method. In this study, the measurement of moment of inertia of turbocharger rotor for 2.0 L spark-ignition engine was carried out. First, an experimental equipment using a trifilar method was designed and fabricated. Some optical devices, that is, photo sensor, counter, convex lens, etc, were used to increase the accuracy of the measurement. Second, error sensitivity for the equipment was analyzed. The error of period time and the radius can give big affects to the accuracy of the moment of inertia. When the amount of error of these two were each 1.0 %, maximum error of the moment of inertia was under 3.0 %. Third, the calibration for the equipment was performed using a calibration rotor which has similar shape to turbine rotor but simple. Calculated value from CAD software and measured one for the calibration rotor were compared. The total error of the equipment and the measurement is about 1.3 %. This result shows that the equipment can give the good result with resonable accuracy. Finally the moment of inertia of the turbine rotor and compressor wheel were measured. The coefficient of variations, the ratio of standard deviation to mean value, were reasonably small at 0.57 % and 0.73 % respectively. Therefore this equipment is suitable for the measurement of the moment of inertia of the turbine rotor and compressor wheel.

Inertia Identification Algorithm for High Performance Speed Control of Electric Motor (고성능 전동기 속도제어를 위한 관성추정 알고리즘)

  • Lee Sang-Cheol;Kim Heung-Geun;Choi Jong-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.5
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    • pp.436-442
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    • 2005
  • This paper proposes an estimation algorithm to find the moment of inertia, which is essential to design high performance controller for motor drive system. The algorithm finds the moment of inertia observing the position error signal, which contains an error information of moment of inertia, generated by speed observer. Moreover, the proposed algorithm is easily realized in the observer-based speed detection method. The simulation and experimental results are also presented to confirm the performance of moment of inertia estimation method, which shows that the moment of inertia converges to the actual value within several seconds. The speed control responses and the designed speed controller performance match well.

Inertia Latch Design for Micro Optical Disk Drives (초소형 광디스크 드라이브용 관성 래치 설계)

  • 김경호;김유성;이승엽;유승헌;김수경
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.1157-1164
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    • 2003
  • Dynamic Load/unload (L/UL) mechanism is an alternative to the contact start stop (CSS) technology which eliminates stiction and wear failure modes associated with CSS. Other benefits of L/UL include increased areal density due to smooth disk surfaces, thinner overcoats, and lower head flying height Improved shock resistance due to elimination of head slap, and reduced power consumption. Inertia latch mechanism becomes important for mobile disk drives because of non operating shock performance. Various types of latch designs have been introduced in hard disk drives to limit a rotary actuator from sudden uncontrolled motion. In this paper, a single spring inertia latch is introduced for a small form optical disk drive, which uses a rotary actuator for moving an optical pick-up. A new small inertia latch with single spring is designed to ensure both feasible and small size. The shock performance of the new inertia latch is experimentally verified.

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A Study of the Effect of Inaction Inertia on Intention to Purchase Fashion Products -Focusing on Moderation of Price Levels- (무행동 관성 효과가 패션 상품의 구매 의도에 미치는 영향 -상품 가격대 조절효과를 중심으로-)

  • Choi, Hyemin;Lee, Eun-Jung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.43 no.1
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    • pp.154-166
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    • 2019
  • Consumers believe it is more profitable to buy products at a discount price than at a fixed price. However, consumers who miss an opportunity for a discount would experience regret; consequently, they may also forgo a purchase despite experiencing regret if a subsequent opportunity was no more attractive than the initial one. This phenomenon has been conceptualized as inaction inertia. In this study we investigate if consumers showed behavior of inaction inertia under the situation of fashion products purchase as well as if price and involvement had a moderating effect on product purchase. The following are the results of the research based on an empirical investigation. First, according to the results of influence of inaction inertia on purchase intention, respondents exposed to scenario of experiencing similar price discount in the past, both under high-price situations and low-price situations, made statistically fewer responses than those exposed to situations without such experience; therefore, effect of inaction inertia could be confirmed. Second, the moderating effect of product price on relationships between inaction inertia and purchase intention was not statistically significant.

Flapwise Bending Vibration of Rotating Timoshenko Beams with Concentrated Mass Moment of Inertia (집중 질량 및 관성모멘트를 갖는 회전하는 티모센코 보의 면외굽힘 진동)

  • 박정훈;유홍희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.110-115
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    • 1997
  • A modeling method for the bending vibration analysis of rotating Timoshenko beams with concentrated mass and mass moment of inertia is presented. The shear and rotary inertia effects become critical for the accurate estimation of the natural frequencies and modeshapes as the slenderness ratio decreases. The effect of the concentrated mass and mass moment of inertia on the natural frequencies are also investigated with the modeling method.

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Capital Structure Inertia and Product Market Competition (자본구조의 관성과 상품시장 경쟁간의 관계)

  • Choi, Chilsun;Son, Pando;Yi, Sangeun;Kim, Sanghyun
    • International Area Studies Review
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    • v.21 no.2
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    • pp.143-169
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    • 2017
  • This paper empirically examines how capital structure inertia varies across industries and there is different in industries, and whether this fact is explained by product market competition using non-financial firms listed in KOSP market over periods of 1981 to 2015. In empirical test, I find that firms with more competition environment tend to have inertia behavior in making decision of capital structure. This implies that it is explained by debt discipline effect and it is substitution for product market competitions. Also I find that manager tends to take action actively making decision of capital structure when product market competition is low. Also I show that they use debt to constraint the free cash flow. As a result, I conclude that Korean non-financial firms do not have more strong inertia behavior in capital structure rather than U.S. firms. Second, using OLS estimation, inertia effect disappears while there is strong inertia effect in relationship between inertia and product market competition. This result suggests that transaction cost is not key factor in explaining inertia behavior of capital structure.

A Study on the System Parameters to Reduce the Idle Gear Rattle (기어 래틀 저감을 위한 시스템 파라미터 연구)

  • 안병민;장일도;최은오;홍동표;정태진
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.88-96
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    • 1998
  • The rattle noise is the most significant in many kinds of manual gearbox nioses, which is generated at the idle stage of the engine operation. The main torsional vibrat- ion source of the driveline is the fluctuation of the engine torque. The gear rattle is impacts generating in the backlash of the free gear due to this torsional vibration. Many researchers reported the clutch torsional characteristic optimization method to reduce the idle gear rattle but only few of them give sufficient consideration to the system parameters like gear backlash, drag torque, system inertia, inertia distribution, engine torque fluctuation, idle engine rotation speed, and accessory load. In this paper, influence rate of system parameters on the gear rattle is presented and counterplans like backlash reduction, drag torque increase, inertia addition, inertia distribution modification and engine torque characteristic control are suggested.

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A Case Study on the Structural Design Improvement of a Mold M/C's Head Slides for Smooth Motion Regarding to Inertia and Moment Impact (금형가공센터 고속 이송체의 성능 안정화를 위한 설계개선 사례)

  • 최영휴;홍진현;최응영;이재윤;김태형;최원선
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.410-415
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    • 2004
  • Heavy-weight head slides may cause excessive inertia impact & moment on the machine tool structure when they move or stop abruptly during operation. Consequently these inertia impact and unbalanced moment bring transient vibrations and rough sliding motions on the machine structure. Machine tool engineers have tried many kind of feed-slide designs in order to solve this problem; for example, the design optimization of the moving structure for minimum weight and maximum stiffness, box-in-box type slide design, and so on. In this article, force and moment equilibrium equations regarding to the inertia force & moment were derived for each one of a mold M/C's head slides. Furthermore, five different design configurations of head slide assembly were reviewed for its design improvement regarding to force & moment calculations and finite element structural analysis results.

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