• 한국소음진동공학회논문집
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• 제18권2호
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• pp.153-159
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• 2008

General coil spring has linearity. However, disc spring has non-linearity so that using this non-linearity disc spring can be designed to do shock-absorbing in cases we need because shock response also has non-linearity. By changing the shape and stacking number, it is satisfactory with response of displacement, velocity and acceleration. Conventionally, disc spring was used to control the vibration against huge load and limited space. However, it is limitedly used because of difficulty of the designing guidance. Therefore, disc spring is needed to study further in order to apply it widely. Response of disc spring is compared to response of coil spring by changing $h_o/t$ ratio with computer simulation and the usage of disc spring is increased through analysis of effect of design factors. The purpose of this paper is that the shock response of disc spring is calculated through numerical simulation and effect of $h_o/t$ and stiffness is analyzed to broad usage so that design factor of disc spring is presented.

• 대한기계학회논문집
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• 제15권6호
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• pp.1831-1838
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• 1991

본 연구에서는 와핑과 두 단면중심의 불일치에 의해 발생하는 기하중심의 이 동을 고려한 등매개변수보요소를 개발하여 스프링단면의 응력해석을 수행하고 그 결과 를 다음과 같이 검증할 것이다.우선 본 연구에 사용된 보요소가 이 두 효과를 효과 적으로 표현하고 있는지를 확인하기 위해서 간단한 비틀림실험과 비교할 것이다. 또 한 2차원문제에 대해서 입체요소를 이용한 결과와 비교하고, 원통형 스프링모델의 해 석결과를 Nagaya의 해석결과와 비교함으로써 실제 스프링해석에 효과적으로 적용될 수 있음을 보일 것이다.

• 제어로봇시스템학회논문지
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• 제5권2호
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• pp.208-219
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• 1999

Springs have been employed in a wide range of mechanical systems. This work deals with the concept of an adaptable spring mechanism which can arbitrarily modulate its spring characteristics. The adaptable spring is desired for enhancing performances of various mechanical systems employing springs. We demonstrate that such adaptable springs can be realized by adapting anthropomorphic musculoskeletal structures of the human upper-extremity, which possesses highly nonlinear kinematic-coupling among redundant muscles existing in its structures. This phenomenon has been explained by several human arm models. Based on the analysis results, we propose multi-degree-of-freedom spring mechanisms resembling the musculoskeletal structure of the human upper-extremity, and verifiy the applicability of these mechanisms through simulation.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2006년도 학술발표회 논문집
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• pp.471-478
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• 2006

This paper presents the results of experimental studies of the mechanical characteristics of the Coil Spring and Viscous Damper system. The Coil Spring and Viscous Damper systems were selected for the isolation of Emergency Diesel Generator (EDG) which is located in Nuclear Power Plant (NPP). The Coil Spring and Viscous Damper systems were developed for, the operating vibration isolation and seismic isolation for scaled Model EDG System. The damping properties of the viscous damper changes as the variation of velocity. As a results, nonlinear damping characteristics of viscous damper system were evaluated.

• 대한기계학회논문집A
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• 제28권9호
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• pp.1352-1358
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• 2004

The mechanical spring is one of widely used machine elements. Among various kinds, flat-type spring loaded by a rotating pin was studied. A flat spring was simplified to a cantilever beam, and numerical analysis was attempted. Since the loading pin rotates about a separate axis from the fixed spring or vice versa, the location, direction, and magnitude of the contact force including normal contact and friction loads vary accordingly. Meanwhile, the spring is deformed substantially as the relative motion progresses. Therefore, this problem needs to be formulated taking the follower loading characteristics and geometrical non-linearity into account. Derived nonlinear differential equation was solved to yield the spring deflection, contact force and the torque to rotate the pin, and the result was compared with a finite element solution. Also, the influences of principal design parameters were studied. The proposed methodology is expected to be useful for the design of pin-loaded flat spring and the prevention of mechanical failures in the form of yielding or fatigue failure of spring or severe wear of the components.

• 한국지진공학회논문집
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• 제11권2호
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• pp.19-26
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• 2007

본 연구에서는 Coil Spring과 Viscous Damper 시스템의 동특성 분석을 위한 특성실험을 수행하였다. Coil Spring과 Viscous Damper 시스템은 원자력발전소 비상디젤발전기의 진동저감 및 지진력 저감을 위한 장치로 선정되었다. Viscous Damper 가진 속도에 따라서 그 특성이 다르게 나타나기 때문에 그 영향을 평가하여 진동저감과 지진력 저감효과를 동시에 고려할 수 있는 장치로서의 성능을 평가하고자 하는 것이다. 실험결과 수평방향의 경우 속도의존 비선형 거동이 두드러지게 나타나고 있는 반면 연직방향은 그러한 특성이 미미한 것으로 나타났다. 강성과 감쇠 모두 설계값보다 고평가 되고 있는 것으로 나타나서 전체 시스템의 면진 및 진동저감시 영향을 미칠 수 있는 것으로 나타났다.

• 한국전산구조공학회논문집
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• 제13권2호
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• pp.189-196
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• 2000

본 연구에서는 반복하중을 받는 프리캐스 콘크리트 판구조의 비선형 거동을 예측할 수 있는 해석방법을 제시하고자 한다. 프리캐스트 콘크리트 판은 탄성유한요소로 이상화하고, 벽판이 교차하는 접합부는 비선형 스프링요소로 모델링한다. 특히, 접합부에서 발생하는 전단, 압축과 인장거동을 묘사할 수 있도록 압축-인장 요소와 전단요소를 개발하고 각 스프링 요소의 강도와 강성은 기존연구자들에 의해 제시된 연구결과를 이용하여 구축한다. 구축된 모델을 비선형 해석프로그램인 DRAIN-2DX에 적용시켜 프리캐스트 콘크리트 판구조의 비선형 이력특성을 예측한다. 제안된 방법의 적합성을 평가하기 위하여 기존에 실험된 실험체를 대상으로 비선형 해석을 실시하고 그 결과를 비교하였으며, 그 결과 강도, 강성, 에너지 소산성능 및 횡변위 등에 대하여 실험결과와 해석결과가 좋은 대응을 보이는 것으로 나타났다. 이로부터 제안된 방법을 이용하여 대형콘크리트 판구조체의 비선형 이력특성을 적절히 예측할 수 있는 것으로 보여진다.

• Advances in aircraft and spacecraft science
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• 제7권4호
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• pp.291-308
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• 2020

In this paper, a numerical method is utilized to study the effect of a new vibration absorber on vibration response of the stiffened functionally graded (SFG) cylindrical shell under a couple of axial and transverse compressions. The material composition of the stiffeners and shell is continuously changed through the thickness. The vibration absorber consists of a mass-spring-damper system which is connected to the ground utilizing a linear local damper. To simplify, the spring element of the vibration absorber is called global potential. The von Kármán strain-displacement kinematic nonlinearity is employed in the constitutive laws of the shell and stiffeners. To consider the stiffeners in the model, the smeared stiffener technique is used. After obtaining the governing equations, the Galerkin method is applied to discretize the nonlinear dynamic equation of system. In order to find the nonlinear vibration responses, the fourth order Runge-Kutta method is utilized. The influence of the stiffeners, the dynamic absorber parameters on the vibration behavior of the SFG cylindrical shell is investigated. Also, the influences of material parameters of the system on the vibration response are examined.

• 한국해양공학회지
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• 제12권3호통권29호
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• pp.19-30
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• 1998

In this paper, the dynamic analysis of a dolphin system for mooring a floating structure such as barge mounted plant is studied. The characteristics of the soil-pile system are simplified by a set of equivalent spring elements at the mudline. To evaluate the equivalent spring constants, the finite difference method is used. Since the characteristics of the soil-pile system are nonlinear in case of soft foundation, the nonlinear dynamic analysis technique is needed. The Newmark $beta$ method incorporating the modified Newton-Raphson method(initial stiffness method) is used. A numerical analysis is performed on two mooring dolphin systems on soft foundation and rock foundation. In case of the rock foundation, the characteristics are found to be nearly linear, so the linear dynamic analysis may be sufficient to consider the foundation effect. But in case of soft foundation, the non-linearity of the foundation appears to be very signigicant, so the nonlinear dynamic analysis si needed.

• 한국정밀공학회지
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• 제11권4호
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• pp.99-105
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• 1994

In this study, the transverse and the torsional vibration analyses of a precision dynamic drive system with the magnetic coupling are accomplished. The force of the magnetic coupling is regarded as an equivalent transverse stiffness, which has a nonlinearity as a function of the gap and the eccentricity between a driver and a follower. Such an equivalent stiffness is calculated by and determined by the physical law and the calculated equivalent stiffness is modelled as the truss element. The form of the torque function transmitted through the magnetic coupling is a sinusoidal and such an equivalent angular stiffness, which represents the torque between a driver and a follower, is modelled as a nonlinear spring. The main spindle connected to a follower is assumed to a rigid body. And then finally we have the nonlinear partial differential equation with respect to the angular displacements. Through the procedure mentioned above, we accomplish the results of the torsional vibration analysis in a spindle system with the magnetic coupling.