• Title/Summary/Keyword: Acceleration Effect

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Effect on Transient Performance of Driver's Acceleration Type in MPI Gasoline Engine (운전자의 가속타입이 MPI 가솔린엔진의 과도성능에 미치는 영향)

  • 곽지현;전충환;장영준
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.75-81
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    • 2000
  • To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration($\DeltatI_{nj}$) and air excess ratio($\lambda$) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

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Acceleration analysis by using line geometry and its application to dynamics (선 기하를 이용한 가속도 해석과 동역학에의 적용)

  • 홍만복;최용제
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.912-915
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    • 2002
  • It has been known that general velocity and force of a rigid body in space can be described in forms of a twist and a wrench by use of screws. However, the geometrical meaning of acceleration has not been clearly disclosed. It has been a normal practice to analyze or synthesize the acceleration effect of manipulator using some complex mathematical equations, which do not represent any geometrical meanings. In other words, such a technique doesn't clearly provide information about the overall acceleration state of manipulator at that instant. In this study, the geometrical meaning of acceleration of a rigid body has been investigated and thereby a geometrical procedure which can be applied to inverse acceleration analysis of a general non-redundant manipulator is presented as an application.

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Fatigue Effect on Lifting Acceleration During Frequent Liftings (규칙적 들어올리기 작업에 있어서의 들기 가속도와 피로도와의 관계연구)

  • Kim, Young-Joun
    • Journal of the Ergonomics Society of Korea
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    • v.21 no.1
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    • pp.27-32
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    • 2002
  • The objective of this study was to investigate the effects of fatigue, caused by frequent manual lifting. on lifting velocity and lifting acceleration. Ten male volunteers performed lifting at a rate of 4 times per minute, continuously, for two hours using the free-style posture A box($30cm{\times}30cm{\times}20$) with a fixed weight (15.9 Kg) was used as the load for lifting, Heart rate, oxygen consumption, and EMG were also measured to estimate the level of fatigue, The posture as well as acceleration was recorded. The results showed that the lifting acceleration at the end of two hour increased significantly (20%, p<0.001) compared to the acceleration after fifteen minutes of lifting. It was also found that subjects changed their lifting postures as the result of fatigue. All subjects also indicated pain in their upper legs and the lower back at the conclusion of the experiment.

SIMM Method Based on Acceleration Extraction for Nonlinear Maneuvering Target Tracking

  • Son, Hyun-Seung;Park, Jin-Bae;Joo, Young-Hoon
    • Journal of Electrical Engineering and Technology
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    • v.7 no.2
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    • pp.255-263
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    • 2012
  • This paper presents the smart interacting multiple model (SIMM) using the concept of predicted point and maximum noise level. Maximum noise level means the largest value of the mere noises. We utilize the positional difference between measured point and predicted point as acceleration. Comparing this acceleration with the maximum noise level, we extract the acceleration to recognize the characteristics of the target. To estimate the acceleration, we propose an optional algorithm utilizing the proposed method and the Kalman filter (KF) selectively. Also, for increasing the effect of estimation, the weight given at each sub-filter of the interacting multiple model (IMM) structure is varying according to the rate of noise scale. All the procedures of the proposed algorithm can be implemented by an on-line system. Finally, an example is provided to show the effectiveness of the proposed algorithm.

A Study on Techniques for Evaluating Collision Acceleration of Rollingstock (열차의 충돌가속도 크기를 평가하기 위한 방법 연구)

  • Kim, Woon-Gon;Kim, Geo-Young;Koo, Jeong-Seo
    • Proceedings of the KSR Conference
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    • 2009.05b
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    • pp.233-237
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    • 2009
  • In this study, we suggest that several approaches to evaluate the collision acceleration value of a car in the article 35 and the guideline 16 of Korean rolling stock safety regulation. There are various methods to evaluate collision acceleration such as; a displacement comparison method by the double integration of filtered acceleration data, a velocity comparison method by the integration of filtered acceleration data, an analysis method of time-velocity curve, or a differential method of time-velocity curve. We compared these methods one another using 1D dynamic simulation model composed of nonlinear dampers, springs and bars, and masses. Also, we applied these methods to a hybrid model, which is made of 3D shell element model and 2D collision dynamics model, in order to evaluate whether 1D force-displacement curve modeling for energy absorbing structures have an effect on the collision acceleration levels or not.

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Effect of design spectral shape on inelastic response of RC frames subjected to spectrum matched ground motions

  • Ucar, Taner;Merter, Onur
    • Structural Engineering and Mechanics
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    • v.69 no.3
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    • pp.293-306
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    • 2019
  • In current seismic design codes, various elastic design acceleration spectra are defined considering different seismological and soil characteristics and are widely used tool for calculation of seismic loads acting on structures. Response spectrum analyses directly use the elastic design acceleration spectra whereas time history analyses use acceleration records of earthquakes whose acceleration spectra fit the design spectra of seismic codes. Due to the fact that obtaining coherent structural response quantities with the seismic design code considerations is a desired circumstance in dynamic analyses, the response spectra of earthquake records used in time history analyses had better fit to the design acceleration spectra of seismic codes. This paper evaluates structural response distributions of multi-story reinforced concrete frames obtained from nonlinear time history analyses which are performed by using the scaled earthquake records compatible with various elastic design spectra. Time domain scaling procedure is used while processing the response spectrum of real accelerograms to fit the design acceleration spectra. The elastic acceleration design spectra of Turkish Seismic Design Code 2007, Uniform Building Code 1997 and Eurocode 8 are considered as target spectra in the scaling procedure. Soil classes in different seismic codes are appropriately matched up with each other according to $V_{S30}$ values. The maximum roof displacements and the total base shears of considered frame structures are determined from nonlinear time history analyses using the scaled earthquake records and the results are presented by graphs and tables. Coherent structural response quantities reflecting the influence of elastic design spectra of various seismic codes are obtained.

Design Shear Force Reduction Factor of Upper Structure in Seismic Base-isolated System Considering Response Acceleration Decrement Effect (면진구조의 응답가속도 감소효과를 고려한 상부구조의 설계전단력 저감계수)

  • Chen, Hao;Oh, Sang-Hoon
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.35 no.7
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    • pp.165-170
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    • 2019
  • The structural damage caused by earthquake to the upper structure of seismic base-isolated system can be suppressed effectively because it is designed to concentrate the input energy on the seismic isolation floor. Further, the response acceleration of seismic base-isolated system can be greatly reduced compared to the seismic structure because of the long period, which means that the design shear force of the seismic base-isolated system can be reduced appropriately. However, when the design shear force is determined to be reduced, the design stiffness will decrease, and the response acceleration will increase oppositely. Therefore, for finding the extent to which the design shear force of the upper structure can be reduced, this paper considered the seismic base-isolated structure as the analytical model and proposed the design shear force reduction factor of the base-isolated structure through the dynamic response analysis, while considering the decrement effect of response acceleration. The research result shows that the response acceleration of the isolated the upper structure can be reduced by 50%~70% of the seismic structure under the same design conditions, and the design shear force can be reduced by up to 40%. By increasing the design stiffness over to 1.8 times of the original design value, the design shear force can be reduced to the same extent as the response acceleration can be reduced compared to the seismic structure.

Evaluation of Equivalent-Static Floor Acceleration for Seismic Design of Non-Structural Elements (비구조요소의 내진설계를 위한 등가정적 층가속도 평가)

  • Jun, Su-Chan;Lee, Cheol-Ho;Bae, Chang-Jun;Kim, Sung-Yong
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.36 no.3
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    • pp.121-128
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    • 2020
  • In this paper, the ASCE 7 equivalent static approach for seismic design of non-structural elements is critically evaluated based on the measured floor acceleration data, theory of structural dynamics, and linear/nonlinear dynamic analysis of three-dimensional building models. The analysis of this study on the up-to-date database of the instrumented buildings in California clearly reveals that the measured database does not well corroborate the magnitude and the profile of the floor acceleration as proposed by ASCE 7. The basic flaws in the equivalent static approach are illustrated using elementary structural dynamics. Based on the linear and nonlinear dynamic analyses of three-dimensional case study buildings, it is shown that the magnitude and distribution of the PFA (peak floor acceleration) can significantly be affected by the supporting structural characteristics such as fundamental period, higher modes, structural nonlinearity, and torsional irregularity. In general, the equivalent static approach yields more conservative acceleration demand as building period becomes longer, and the PFA distribution in long-period buildings tend to become constant along the building height due to the higher mode effect. Structural nonlinearity was generally shown to reduce floor acceleration because of its period-lengthening effect. Torsional floor amplification as high as 250% was observed in the building model of significant torsional irregularity, indicating the need for inclusion of the torsional amplification to the equivalent static approach when building torsion is severe. All these results lead to the conclusion that, if permitted, dynamic methods which can account for supporting structural characteristics, should be preferred for rational seismic design of non-structural elements.

Design of the Main Nozzle with Different Acceleration Tube and Diameter in an Air-Jet Loom

  • Jeong, Seok-Yoon;Kim, Kyung-Hoon;Choi, Jin-Hwan;Lee, Chan-kyu
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.1
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    • pp.23-30
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    • 2005
  • The air-jet loom represents a major step in the development of shutterless weaving due to its ability to weave a wide range of yarns at high speeds. The air-jet weaving involves inserting a pre-measured length of yarn through the wraps, which is shed by means of compressed air. The analysis of air flow characteristic of the main nozzle and acceleration tube is required for improving the loom performance. In this paper, we examined the effects of the main nozzle with different acceleration tubes as well as diameters. Also, we compared the performance of a straight-type tube with a Laval-type tube and the effect of installing a suction hole on the acceleration tube.

Flow Characteristics of the Main Nozzle with different Acceleration Tube and Diameter in an Air-Jet Loom (에어젯트 직기에서 가속관 직경변화에 따른 주노즐의 유동특성)

  • Jeong, S.Y.;Kim, K.H.
    • Journal of ILASS-Korea
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    • v.8 no.2
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    • pp.16-23
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    • 2003
  • The Air-jet loom represents a major step in the development of shutterless weaving due to its ability to weave a wide range of yarns at high speeds. The Air-jet weaving involvers, inserting a pre-measured length of yam through the wrap, is sheds by meads of compressed air. The analysis of air flow characteristic of the main nozzle and acceleration tube is required for the loom performance. h this paper We examined the effect of the main nozzle with different acceleration tubes as well as diameters. And also, we compared the performance of straight type tube with laval type tube and of according to be suction hole on the acceleration tube, respectively.

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