• Title/Summary/Keyword: steady-state

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Creep analysis of a rotating functionally graded simple blade: steady state analysis

  • Mirzaei, Manouchehr Mohammad Hosseini;Arefi, Mohammad;Loghman, Abbas
    • Steel and Composite Structures
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    • v.33 no.3
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    • pp.463-472
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    • 2019
  • Initial thermo-elastic and steady state creep deformation of a rotating functionally graded simple blade is studied using first-order shear deformation theory. A variable thickness model for cantilever beam has been considered. The blade geometry and loading are defined as functions of length so that one can define his own blade profile and loading using any arbitrary function. The blade is subjected to a transverse distributed load, an inertia body force due to rotation and a distributed temperature field due to a thermal gradient between the tip and the root. All mechanical and thermal properties except Poisson's ratio are assumed to be longitudinally variable based on the volume fraction of reinforcement. The creep behaviour is modelled by Norton's law. Considering creep strains in stress strain relation, Prandtl-Reuss relations, Norton' law and effective stress relation differential equation in term of effective creep strain is established. This differential equation is solved numerically. By effective creep strain, steady state stresses and deflections are obtained. It is concluded that reinforcement particle size and form of distribution of reinforcement has significant effect on the steady state creep behavior of the blade.

Control of a continuous flow stirred tank reactor with consecutive reactions (연속반응이 일어나는 연속류 교반조 반응기의 제어)

  • 김종엽;이현구
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.232-237
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    • 1986
  • Theoretical studies are performed for a nonisothermal CFSTR in which consecutive reactions take place. The local dynamic stability of an unstable steady state is investigated with relation to variations in the controller gain when the temperature is subjected to a proportional control. The control has significant in fluences upon the stability of the high temperature steady state as well as that of the intermediate steady state.

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LOCAL REGULARITY OF THE STEADY STATE NAVIER-STOKES EQUATIONS NEAR BOUNDARY IN FIVE DIMENSIONS

  • Kim, Jaewoo;Kim, Myeonghyeon
    • Journal of the Chungcheong Mathematical Society
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    • v.22 no.3
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    • pp.557-569
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    • 2009
  • We present a new regularity criterion for suitable weak solutions of the steady-state Navier-Stokes equations near boundary in dimension five. We show that suitable weak solutions are regular up to the boundary if the scaled $L^{\frac{5}{2}}$-norm of the solution is small near the boundary. Our result is also valid in the interior.

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BIFURCATION ANALYSIS OF A SINGLE SPECIES REACTION-DIFFUSION MODEL WITH NONLOCAL DELAY

  • Zhou, Jun
    • Journal of the Korean Mathematical Society
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    • v.57 no.1
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    • pp.249-281
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    • 2020
  • A reaction-diffusion model with spatiotemporal delay modeling the dynamical behavior of a single species is investigated. The parameter regions for the local stability, global stability and instability of the unique positive constant steady state solution are derived. The conditions of the occurrence of Turing (diffusion-driven) instability are obtained. The existence of time-periodic solutions, the existence and nonexistence of nonconstant positive steady state solutions are proved by bifurcation method and energy method. Numerical simulations are presented to verify and illustrate the theoretical results.

Hearing Test in Infant and Young Children Using MASTER (Multiple Auditory Steady-State Response(MASTER)을 이용한 유소아의 청력검사)

  • Lee, Hak-Sun;Kim, Shi-Chan
    • Speech Sciences
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    • v.11 no.4
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    • pp.143-150
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    • 2004
  • This study was done to compare thresholds between those of Auditory Brainstem Response (ABR) with clicks or tonebursts and Multiple Auditory Steady-State Response (MASTER). The results would give a promising tool for evaluating frequency-specific hearing sensitivity in infants or young children. The correlation coefficient value between the click ABR thresholds and MASTER thresholds at carrier frequencies, 500, 1,000, 2,000 Hz, and 4,000 Hz was obtained at Pearson 0.91, 0.94, 0.93, and 0.91.

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Steady State Analysis of a Stand-alone Induction Generator with AC Rotor Excitation (회전자 문류\ulcorner\ulcorner방식의 자립형 유도발전기의 정상상태 해석)

  • 박민호;정승기;이진우
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.37 no.1
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    • pp.33-39
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    • 1988
  • In this paper, a stand-alone wound rotor induction generator system is proposed and its steady state characteristics are analyzed. It is shown that the self-excitation of the system can be acheined by exciting the rotor through the PWM inverter. The analysis is based upon the eguivalent circuit and the steady state dq model of the mahine. The results show that the proposed system can be made to generate constant voltage constant frequency power for various speed and load conditions.

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DETERMINATION OF TRANSIENT WEAR DISTANCE IN THE ADHESIVE WEAR OF A6061 ALUMINIUM ALLOY REINFORCED WITH ALUMINA PARTICLES

  • Yang, L.J.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.217-218
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    • 2002
  • An integrated adhesive wear model was proposed to determine the transient wear and steady-state wear of aluminium alloy matrix composites. The transient wear volume was described by an exponential equation, while the steady-state wear was governed by a revised Archard equation, in which both the transient wear volume and transient sliding distance were excluded. A mathematical method was developed to determine both the transient distance and the net steady-state wear coefficient. Experimental wear tests were carried out on three types of commercial A6061 aluminum alloy matrix composites reinforced with 10%, 15% and 20% alumina particles. More accurate wear coefficient values were obtained with the proposed model. The average standard wear coefficient, as determined by the original Archard equation, was found to be about 51% higher.

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A Study on the Characteristics of Heat Distribution of Welded Joint on the Steel Structure with Thick Plate (厚板 鋼構造物 熔接이음부의 熱分布 特性에 關한 硏究)

  • 방한서;김종명
    • Journal of Welding and Joining
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    • v.13 no.1
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    • pp.138-144
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    • 1995
  • Recently, as the industrial structure tends to become large, the thickness of structural plate becomes thicker. Therefore, the thicker the plate of welded structure is, the larger the shape of welded joint. The effect of large heat input makes large heat affected zone(HAZ). These bring to complict welding residual stress and to weaken material, which may cause extremely harm to the safety of structures. Nevertheless, welding is design is regulated by the KS, JIS or standard in the resister of shipping such as KR, ABS or LR. However, these rules are based on rather experimental than theoretical. In this study, the computer program of heat conduction, considering un-steady state and quasi-steady state, is developed for optimizing(minimizing) a shape of welded joint. The characteristics of heat on the welded joints with various shapes are clarified by the results of the analyses.

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Fuzzy Control Algorithm Eliminating Steady-state Position Errors of Robotic Manipulators (로봇 머니퓰레이터의 정상상태 위치오차를 제거할 수 있는 퍼지제어 알고리듬)

  • Kang, Chul-Goo;Kwak, Hee-Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.3
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    • pp.361-368
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    • 1997
  • In order to eliminate position errors existing at the steady state in the motion control of robotic manipulators, a new fuzzy control algorithm is propeosed using three variables, position error, velocity error and integral of position errors as input variables of the fuzzy controller. Although the number of input variables of the fuzzy controller is increased from two to three, the number of fuzzy control rules is just increased by two. Three dimensional look-up table is used to reduce the computational time in real-time control, and a technique reducing the amount of necessary memory is introduced. Simulation and experimental studies show that the position errors at the steady state are decreased more than 90% compared to those of existing fuzzy controller when the proposed fuzzy controller is applied to the 2 axis direct drive SCARA robot manipulator.

Controller Design by Error Shape and Steady-State Error Analysis for a Feed Drive System in CNC Milling Machine (CNC 밀링머신 이송장치의 오차유형 및 정상상태 오차해석에 의한 제어기 설계)

  • Lee Gun-Bok;Gil Hyeong-Gyeun
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.3 s.168
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    • pp.52-60
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    • 2005
  • This paper deals with the position control fur a feed drive system in CNC milling machine, which utilizes a modified error signal for the elimination of steady-state error. A linear time-invariant (LTI) system has consistent properties in response to standard test signal inputs. Those also appear in an error curve acquired from the response. From such properties, constructed is an error model for the position control of the feed drive. And then added is the output of the error model to the current error signal. Consequently the resulting proportional control system brings performance improvement in view of the steady-state error. The effectiveness of the proposed scheme is confirmed through simulations and experiments.