• 제목/요약/키워드: Elastic Spring

검색결과 394건 처리시간 0.022초

부가 스프링 지지를 갖고 유동유체에 의한 외팔 수직 파이프의 동적 안정성 (Dynamic Stability of a Vertical Cantilevered Pipe Conveying Fluid with Additional Spring Supports)

  • 류봉조;정승호;이종원
    • 한국소음진동공학회논문집
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    • 제12권12호
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    • pp.979-985
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    • 2002
  • The paper presents the dynamic stability of a vertical cantilevered pipe conveying fluid and haying translational linear spring supports. Real pipe systems may have some elastic hanger supports or other mechanical attached parts. which can be regarded as attached spring supports. Governing equations are derived by energy expressions, and numerical technique using Galerkin's method is applied to the equations of small motion of the pipe. Effects of spring supports on the dynamic stability of a vortical cantilevered pipe conveying fluid are fully investigated for various locations and spring constants of elastic supports.

능동형 현가장치를 위한 가변 강성 직렬 탄성 액추에이터 설계 (Variable Stiffness Series Elastic Actuator Design for Active Suspension)

  • 방진욱;최민식;이동형;박정호;박은재;이근일;이장명
    • 로봇학회논문지
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    • 제14권2호
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    • pp.131-138
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    • 2019
  • In this study, we developed an FSEA(Force-sensing Series Elastic Actuator) composed of a spring and an actuator has been developed to compensate for external disturbance forced. The FSEA has a simple structure in which the spring and the actuator are connected in series, and the external force can be easily measured through the displacement of the spring. And the characteristic of the spring absorbs the shock to the small disturbance and increases the sense of stability. It is designed and constructed to control the stiffness of such springs more flexibly according to the situation. The conventional FSEA uses a fixed stiffness spring and the actuator is not compensated properly when it receives large or small external force. Through this experiment, it is confirmed that FSEA compensates the external force through the proposed algorithm that the variable stiffness compensates well for large and small external forces.

너비감소 판형 홀다운스프링 집합체의 탄성강성도 평가 (Estimation of the Elastic Stiffness of TW-HDS Assembly)

  • 송기남
    • 대한기계학회논문집A
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    • 제21권1호
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    • pp.180-187
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    • 1997
  • A formula for estimating the elastic stiffness of TW-HDS with a uniformly tapered width from w$_{0}$ to w$_{1}$ over the length, has been analytically derived based on Euler beam theory and Castigliano's theorem. Elastic stiffnesses of the TW-HDSs designed in the same dimensional design spaces as the KOFA HDSs have been estimated from the derived formula, in addition, a sensitivity study on the elastic stiffness of the TW-HDSs has been carried out. Analysis results show that elastic stiffnesses of the TW-HDSs have been by far higher than those of the KOFA HDSs, and that, as the effects of axial and shear force on the elastic stiffness have been 0.15-0.21%, most of the elastic stiffness is attributed to the bending moment. As a result of sensitivity analysis, the elastic stiffness sensitivity at each design variable is quantified and design variables having remarkable sensitivity are identified. Among the design variables, leaf thickness is identified as that of having the most remarkable sensitivity of the elastic stiffness.

Forced vibration of the elastic system consisting of the hollow cylinder and surrounding elastic medium under perfect and imperfect contact

  • Akbarov, Surkay D.;Mehdiyev, Mahir A.
    • Structural Engineering and Mechanics
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    • 제62권1호
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    • pp.113-123
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    • 2017
  • The bi-material elastic system consisting of the circular hollow cylinder and the infinite elastic medium surrounding this cylinder is considered and it is assumed that on the inner free face of the cylinder a point-located axisymmetric time harmonic force, with respect to the cylinder's axis and which is uniformly distributed in the circumferential direction, acts. The shear-spring type imperfect contact conditions on the interface between the constituents are satisfied. The mathematical formulation of the problem is made within the scope of the exact equations of linear elastodynamics. The focus is on the frequency-response of the interface normal and shear stresses and the influence of the problem parameters, such as the ratio of modulus of elasticity, the ratio of the cylinder thickness to the cylinder radius, and the shear-spring type parameter which characterizes the degree of the contact imperfectness, on these responses. Corresponding numerical results are presented and discussed. In particular, it is established that the character of the influence of the contact imperfection on the frequency response of the interface stresses depends on the values of the vibration frequency of the external forces.

미분구적법을 이용한 핼리컬 스프링의 응력해석 (Stress Analysis of Helical Spring Using DQM)

  • Ki-Jun Kang
    • 한국안전학회지
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    • 제16권4호
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    • pp.208-212
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    • 2001
  • 미분구적법(DQM)을 이용하여 헬리컬 스프링(helical spring)의 2차원적 탄성 문제를 계산하였다. 헬리컬 스프링의 직사각형 및 정사각형 단면적에 축방향 하중(axially loaded)이 작용했을 때의 탄성 전단 응력(elastic shear stress)을 계산하였다. 미분구적법의 결과를 다른 수치해석(successive approximation) 결과와 비교하였으며, 미분구적법은 적은 요소(grid point)를 사용하여 정확한 해석결과를 보여주었다

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후크 벤딩 금형 설계의 전산화에 관한 연구 (Study on the Computerization of Die Design for Bending Hook)

  • 조은정;정호승;정철우;조종래;최일동
    • Journal of Advanced Marine Engineering and Technology
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    • 제26권4호
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    • pp.450-456
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    • 2002
  • Die desig for manufacturing hooks from steel wires has been depended on empirical procedures based on trial and error method. To design die, at first the curvature and bending angle of hook are computed by using AutoCAD and developed program which is composed of Visual Basic. Then spring back should be considered because the elastic recovery of material is very important in bending process. In this study, bending analysis of elastic-plastic materials is applied to predict curvature of hook and spring back. Therefore, systematic procedure of die design for bending hook is achieved to consider elastic recovery in terms of hook shapes. Experimental results are good agreement with calculated results.

Failure mechanisms of a rigid-perfectly plastic cantilever with elastic deformation at its root subjected to tip pulse loading

  • Wang, B.
    • Structural Engineering and Mechanics
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    • 제2권2호
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    • pp.141-156
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    • 1994
  • In this paper, the effect of material elasticity was evaluated through a simple model as proposed by Wang and Yu (1991), for yield mechanisms of a cantilever beam under tip pulse loading. The beam was assumed rigid-perfectly plastic but instead of the usual fully clamped constraints at its root, an elastic-perfectly plastic rotational spring was introduced there so the system had a certain capacity to absorb elastic energy. Compared with a rigid-perfectly plastic beam without a spring root, the present beam-spring model showed differences in the initial plastic hinge position and the minimum magnitude of the dynamic force needed to produce a plastic failure. It was also shown that various failure responses may happen while the hinge travels along the beam segment towards the root, rather than a unique response mode as in a rigid perfectly plastic analysis.

일체형원자로 SMART의 나선형 증기발생기 전열관 코일링 시 스프링백 최소화 방안 (Minimization of the Spring back in the Coiling Process of the Helical Steam Generator Tubes of Integral Reactor SMART)

  • 김용완;김종인;장문희
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.837-842
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    • 2000
  • In the coiling process of helical steam generator tubes of integral reactor SMART, a considerable amount of spring back, which induces dimensional inaccuracy and difficulty in fabrication, has been arised. In this research, an analytical model was derived to evaluate the amount of the spring back for steam generator tubes. The model was developed on the basis of beam theory and elastic-perfectly plastic material property. This model was extended to consider the effect of plastic hardening and the effect of the tensile force on the spring back phenomena. Parametric studies were performed for various design variables of steam generator tubes in order to minimize the spring back in the design stage. A sensitivity analysis has shown that the low yield strength, the high elastic modulus, the small helix diameter, and the large tube diameter result in a small amount of the spring back. The amount of the spring back can be controlled by the selection of adequate design values in the basic design stage and reduced to an allowable limit by the application of the tensile force to the tube during the coiling process.

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탄성지지된 곡선부재의 면내 자유진동 (In-Plane free Vibrations of Curved Members with Elastic Supports)

  • 오상진;강희종;박광규
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 추계학술대회논문집
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    • pp.815-818
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    • 2006
  • This paper deals with the free, in-plane vibrations of curved members with the translational(radial and tangential directions) and rotational springs at the ends. The governing differential equations for the circular curved member are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies and the corresponding mode shapes are obtained over a range of non-dimensional system parameters: the subtended angle, the slenderness ratio, the translational spring stiffness, and the rotational spring stiffness.

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헬리컬 기어의 정밀 냉간 단조에 대한 연구 (Study on Precision Cold Forging of helical Gear)

  • 박용복;양동열
    • 소성∙가공
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    • 제8권4호
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    • pp.384-392
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    • 1999
  • In metal forming, there are problems with recurrent geometric characteristics without explicitly prescibed boundary conditions. In such problems, so-called recurrent boundary conditions must be introduced. In this paper, as a practical application of the proposed method, the precision cold forging of a helical gear has been simulated by a three-dimensional rigid-plastic finite element method and compared with the experiment. The application of recurrent boundary conditions to helical gear forging analysis is proved to be effective and valid. the elastic stress analysis of the die for helical gear forging has been calculated by using the nodal force at the final stage obtained from the rigid-plastic finite element analysis. In order to obtain more precise gear products, the elastic analysis of the die after release of punch and the elastic spring-back analysis of product after ejection have been performed, and the final dimension of the computational product has been in good agreement with that of the experimental product.

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