• Title, Summary, Keyword: Dynamic behavior

Search Result 4,210, Processing Time 0.059 seconds

Dynamic Behavior of Steel Fiber Reinforced Concrete (강섬유콘크리트의 동적거동)

  • 강보순;심형섭
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • /
    • pp.379-384
    • /
    • 2003
  • In this paper, dynamic behavior of steel fiber reinforced concrete(SFRC) by experimental method is discussed. Because of its improved ability to dissipate energy, impact resistance and fatigue behavior, SFRC has a better dynamic behavior than that of plain concrete. Dynamic behavior is influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete and the stress level. Impact resistance and damping in the SFRC has been evaluated from dynamic experimental test data at various levels of cracked states in the elements

  • PDF

An Experimental Investigation on the Dynamic Behavior of an Air Lubricated Tilting Pad Journal Bearing (공기윤활 틸팅패드 저어널 베어링의 동적거동에 관한 실험적 연구)

  • Hwang, Pyung;Kwon, Sung-In
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.325-330
    • /
    • 1999
  • The dynamic behavior analysis of air-lubricated tilting pad journal bearing which considers start-up, running and shutdown Process were performed. By carrying out the experiment of shaft vibration, measurement of the vibration amplitudes supported by air lubricated tilting pad bearing and analysis of the result, we found more accurate dynamic behavior of the system. There were many investigations in these bearings, but dynamic behavior of startup, shutdown and running process were lacked. By using the experimental data we found the accurate dynamic behavior of the system.

  • PDF

The Effects of Team Learning Behavior on Team Effectiveness and the Mediating Effects of Team Dynamic Capabilities (팀 학습행동이 팀 효과성에 미치는 영향과 팀 동적역량의 매개효과)

  • Lee, Kyoun Jae;Hong, Ah Jeong
    • Knowledge Management Research
    • /
    • v.15 no.4
    • /
    • pp.57-78
    • /
    • 2014
  • Since team performance has become one of the core factors for companies' success, companies are putting every effort to raise team productivity. In this vein, the purpose of this study was to examine the influence of team learning behavior upon team dynamic capabilities, team effectiveness, and to verify the mediating effect of team dynamic capabilities in corporations. 312 employees were randomly selected to participate in an questionnaire survey. The result has shown that the static correlation exists between team learning behavior, team dynamic capabilities, and team effectiveness. Team dynamic capabilities mediated the relationship between team learning behavior and team effectiveness. Based on the findings, the study implies that learning behaviors among team members should be supported in order to improve its outcome, and HR representatives must help to develop dynamic capabilities.

An Analysis of Dynamic Behavior of Fluid Dynamic Bearing for Hard Disk Drive Spindle Motor

  • Song, Young-Han;Yoo, Jin-Gyoo;Rhim, Yoon-Chul
    • KSTLE International Journal
    • /
    • v.4 no.1
    • /
    • pp.18-26
    • /
    • 2003
  • Recently, fluid dynamic bearings (EDBs) have important applications in miniature rotating machines such as those found in the computer information storage industry, due to their outstanding low acoustic noise and NRRO (Non-Repeatable Run Out) characteristics. This research investigates the dynamic behavior of fluid dynamic bearings composed of hydrodynamic herringbone groove journal and spiral groove thrust bearing. The five degrees of freedom of FDB are considered to describe the real motion of a general rotor bearing system. The Reynolds equation and five nonlinear equations of motion for the dynamic behavior are solved simultaneously, The incompressible Reynolds equation is solved by using the finite element method (FEM) in order to calculate the pressure distribution in a fluid film and the five equations of motion by using the Runge-Kutta method. The reaction forces and moments are obtained by integrating the pressure along the fluid film. Numerical results are validated by comparing with the previously published experimental and numerical results. As a result the dynamic behavior of FDB spindle such as orbit, floating height, and angular orbit is investigated by considering the conical motion under the static and dynamic load conditions.

A FEM Analysis of Dynamic Behavior for a Slider with Ultra-Thin Air-Film

  • Lim, S.K.;Rhim, Y.C.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.243-244
    • /
    • 2002
  • New type slider with optical components is coming on market for portable and high capacity drive, and it shows great potential in future high performance drive. It is very important that a slider should have a good dynamic behavior. In this paper the dynamic behavior and static characteristics of slider have been investigated numerically by in-house simulation code using FEM.

  • PDF

Rheological Behavior of Viscoelastic Semi-Solid Ointment Base (Vaseline) in Oscillatory Shear Flow Fields (진동전단유동장에서 점탄성 반고형 연고기제(바셀린)의 레올로지 거동)

  • Song, Ki-Won;Chang, Gap-Shik
    • Journal of Pharmaceutical Investigation
    • /
    • v.36 no.1
    • /
    • pp.31-38
    • /
    • 2006
  • Using a Rheometries Dynamic Analyzer (RDA II), the dynamic viscoelastic properties of a semi-solid ointment base (vaseline) in large amplitude oscillatory shear flow fields were measured over a temperature range of $25{\sim}45^{\circ}C$ and the linear viscoelastic behavior in small amplitude oscillatory shear flow fields was investigated over a wide range of angular frequencies. In this article, the nonlinear viscoelastic behavior was reported from the experimentally obtained data and the effect of temperature on this behavior was discussed in detail. In addition, the angular frequency and temperature dependencies of a linear viscoelastic behavior were explained. Finally, the applicability of a time-temperature superposition principle originally developed for polymeric materials was examined using a shift factor. Main results obtained from this study can be summarized as follows : (1) At very small strain amplitude region, vaseline shows a linear viscoelastic behavior independent of the imposed deformation magnitudes. Above a critical strain amplitude $({\gamma}_{0}=0.1{\sim}0.2%)$, however, vaseline exhibits a nonlinear viscoelastic behavior ; indicating that both the storage modulus and dynamic viscosity are sharply decreased with increasing deformation magnitude. (2) In large amplitude oscillatory shear flow fields, an elastic behavior (storage modulus) has a stronger strain amplitude dependence and begins to show a nonlinear behavior at a smaller strain amplitude region than does a viscous behavior (dynamic viscosity). (3) In small amplitude oscillatory shear flow fields, the storage modulus as well as the loss modulus are continuously increased as an increase in angular frequency and an elastic nature is always superior to a viscous behavior over a wide range of angular frequencies. (4) A time-temperature superposition principle can successfully be applicable to vaseline. This finding allows us to estimate the dynamic viscoelastic behavior of vaseline over an extraordinarily extended range (11 decades) of angular frequencies inaccessible from the experimentally measured range (4 decades).

A Numerical Analysis of Dynamic Behavior of Rock Mass with Intense Discontinuities (절리의 방향성을 고려한 암반의 동적거동 수치해석)

  • Ha, Tae-Wook;Yang, Hyung-Sik
    • Tunnel and Underground Space
    • /
    • v.16 no.5
    • /
    • pp.394-404
    • /
    • 2006
  • Dynamic behavior of rock structures depends largely on the dynamic characteristics of ground and input earthquake wave. For blocky rocks with intense discontinuities, the mechanical characteristics of blocks and structural and mechanical characteristics of discontinuities affect overall behavior. In this study, UDEC was adopted to evaluate the dynamic behavior of rocks with various structural characteristics. Obtained results were compared to those of $FLAC^{2D}$, a continuum analysis, and the validity of the method was examined for dynamic analysis of discontinuous rocks for earthquake. Analysis considering the discontinuity showed significant changes in structural shape by the influence of joint behavior, and the behavior by continuum analysis was overestimated.

Experimental Investigation on Dynamic Behavior of Steel Fiber Reinforced Concrete Structures (강섬유콘크리트구조물의 다양한 동적거동에 관한 실험적 연구)

  • Kang, Bo-Soon
    • Journal of the Korean Society for Railway
    • /
    • v.13 no.4
    • /
    • pp.431-439
    • /
    • 2010
  • In this paper, dynamic behavior of steel fiber reinforced concrete(SFRC) by experimental method is discussed. Because of its improved ability to dissipate energy, impact resistance and fatigue behavior, SFRC has a better dynamic behavior than that of plain concrete. Dynamic behavior is influenced by longitudinal reinforcement ratio, volume and type of steel fiber, strength of concrete and the stress level. Impact resistance and fatigue behavior in the SFRC has been evaluated from dynamic experimental test data at various levels of cracked states in the elements.

Behavior factor of vertically irregular RCMRFs based on incremental dynamic analysis

  • Habibi, Alireza;Gholami, Reza;Izadpanah, Mehdi
    • Earthquakes and Structures
    • /
    • v.16 no.6
    • /
    • pp.655-664
    • /
    • 2019
  • Behavior factor of a structure plays a crucial role in designing and predicting the inelastic responses of it. Recently, irregular buildings have been interested in many designers. To design irregular structures, recognizing the inelastic behavior of them is necessary. The main objective of this study is to determine the behavior factor of irregular Reinforced Concrete Moment Resisting Frames (RCMRFs) via nonlinear Incremental Dynamic Analysis (IDA). To do so, first, several frames are designed according to the regulations of the Iranian national building code. Then the nonlinear incremental dynamic analysis is performed on these structures and the behavior factors are achieved. The acquired results are compared with those obtained using pushover analysis and it is shown that the behavior factors acquired from the nonlinear incremental dynamic analysis are somewhat larger than those obtained from pushover analysis. Eventually, two practical relations are proposed to predict the behavior factor of irregular RCMRFs. Since these relations are based on the simple characteristics of frames such as: irregularity indices, the height and fundamental period, the behavior factor of irregular RCMRFs can be achieved efficiently using these relations. The proposed relations are applied to design of four new irregular RCMRFs and the outcomes confirm the accuracy of the aforementioned relations.

A study on the dynamic behavior of Extradosed PSC railway bridge (Extradosed PSC 철도교의 동적거동에 관한 연구)

  • Gill Tae-Soo;Kim Sung-Il;Kim Youn-Tae
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.1248-1253
    • /
    • 2005
  • The study is indispensable for the dynamic behaviors because this Cable-stayed long span bridge ; has a more flexible structure than normal bridge can have weaknesses which are impact factor, deflection and defectives etc. This study analyze the dynamic behavior by an analysis of the moving constant train force on railway with Midas/Civil that is a commercial finite element analysis tool about Extradosed PSC Bridge. Also it will be checked the dynamic behavior features and standard of the dynamic capability.

  • PDF