• 한국음향학회지
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• 제16권1호
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• pp.16-23
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• 1997

강제진동에 의한 외팔보의 동적응답과 진동모드를 연구하였다. Bernoulli-Euler 이론과 유한요소법을 이용하여 외팔보의 고유진동수와 진동모드를 수치해석하고 실험으로 측정하여 비교하였다. 가진주파수를 1Hz에서 70Hz까지 변화시켜 외팔보의 1차, 2차 공진주파수를 구하고, 응답위치에 따른 진동 변위를 측정하여 진동모드를 살펴보았다. 실험결과에서 외팔보의 절점(node)이 1차모드에서는 0.2차모드에서는 0,0.786으로 측정되었다. 외팔보의 공진주파수와 진동모드에 대해 이론적으로 예상했던 결과와 실험으로 측정한 결과가 거의 일치하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.457-462
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• 2002

This paper describe the vibration characteristics of cantilevered beam filled with ERF subjected to variousr electrode charge. The Proposed ER fluids used in the present study consists of starch particles and silicon oil. The ER fluids undergo a phase-change when subjected to an external electric filed. This Paper Presents performance analyses of three types of the cantilevered beam with different electrode gaps and applied electric fields.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.159-168
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• 2005

Noise generated by the blunt trailing edge of lifting surfaces is investigated in this study using fluid structure interaction theory. First, through the eddy modeling, noise generation doe to the flow instability on the rigid trailing edge is surveyed. Then the behavior of elastic cantileverd beam is investigated. Parametric study based on various material properties is employed to analyze the motion of the beam. Moreover, each eigenmode approach of cantilevered beam is used to find when flow induced vibration is resonant. To analyze elastic behavior of cantilever beam efficiently, moving grid generation technique based on non-conservative form of Navier-Stokes equation is used. Equation of the motion associated with the cantilever beam is discretized by the Galerkin procedure with forced vibration. As a consequence, behavior of the elastic cantilevered beam is stable when the first mode natural frequency of the material is relatively higher than that of flow induced pressure fluctuation.

• Structural Engineering and Mechanics
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• 제9권6호
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• pp.569-588
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• 2000

The plastic collapse loads and their locations are predicted for a class of tapered, initially curved, and transversely corrugated cantilevered beams subjected to static tip loading. Results of both closed form and finite element solutions for several rigid perfectly plastic and elastic perfectly plastic beam models are evaluated. The governing equations are cast in nondimensional form for efficient studies of collapse load as it varies with beam geometry and the angle of the tip load. Static experiments for laboratory-scale configurations whose taper flared toward the tip, complemented the theory in that collapse occurred at points about 40% of the beams length from the fixed end. Experiments for low speed impact loading of these configurations showed that collapse occurred further from the fixed end, between the 61% and 71% points. The results may be applied to the design of safer highway guardrail terminal systems that collapse by design under vehicle impact.

• Journal of Mechanical Science and Technology
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• 제16권3호
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• pp.310-319
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• 2002

This paper deals with the analytical modeling, and the experimental verification of the strain rate self-sensing method using a hybrid adaptive filter for a cantilevered piezoelectric beam. The piezoelectric beam consists of two laminated lead zirconium titanates (PZT) on a metal shim. A mathematical model of the beam dynamics is derived by Hamilton's principle and the accuracy of the modeling is verified through the comparison with experimental results. For the strain rate estimation of the cantilevered piezoelectric beam, a self-sensing mechanism using a hybrid adaptive filter is considered. The discrete parts of this mechanism are realized by the DS1103 DSP board manufactured by dSPACE$\^$TM/. The efficacy of this method is investigated through the comparison of experimental results with the predictions from the derived analytical model.

• 한국공간구조학회논문집
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• 제7권1호
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• pp.55-62
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• 2007

곡선보의 고유진동수를 측정하기 우하여 이론적인 해석과 실험 및 유한요소법해석을 실시하였다. 본 논문에서는 모우드해석을 위한 실험에서 얻어지는 결과로부터 곡선보의 동특성의 하나인 고유진동수를 구하였다 먼저, 이론식을 통해 구조물의 동특성을 파악하고, 유한요소해석과 실험에 의한 결과를 비교 검토하여 구조물의 동적해석에 있어서 모우드해석법의 적용성을 보였다.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1355-1360
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• 2006

This paper presents the dynamic stability of a cantilevered Timoshenko beam with a concentrated mass, partially attached to elastic foundations, and subjected to a follower force. Governing equations are derived from the extended Hamilton's principle, and FEM is applied to solve the discretized equation. The influence of some parameters such as the elastic foundation parameter, the positions of partial elastic foundations, shear deformations, the rotary inertia of the beam, and the mass and the rotary inertia of the concentrated mass on the critical flutter load is investigated. Finally, the optimal attachment ratio of partial elastic foundation that maximizes the critical flutter load is presented.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.307-310
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• 2004

The paper presents the numerical and experimental results for the dynamic response vibration of a cantilevered beam subjected to a moving mass with variable speeds. Governing equations of motion under a moving mass were derived by Galerkin's mode summation method taking into account the effects of all forces due to moving mass, and the numerical results were calculated by Runge-Kutta integration method. The effects of the speed, acceleration and the magnitude of the moving mass on the response of the beam are fully investigated. In order to verify numerical results, some experiments were conducted, and the numerical results have a little difference with the experimental ones.

• Structural Engineering and Mechanics
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• 제5권3호
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• pp.257-268
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• 1997

The elastic deflections and Euler buckling loads are investigated for a class of tapered and initially curved cantilevered beams subjected to loading at the tip. The beam's width increases linearly and its depth decreases linearly with the distance from the fixed end to the tip. Unloaded, the beam forms a circular are perpendicular to the axis of bending. The beam's deflection responses, obtained by solving the differential equations in closed form, are presented in terms of four nondimensional system parameters: taper ratio ${\kappa}$, initial shape ratio ${\Delta}_0$, end load ratio f, and load angle ${\theta}$. Laboratory measurements of the Euler buckling loads for scale models of tapered initially straight, corrugated beams compared favorably with those computed from the present analysis. The results are applicable to future designs of the end structures of highway guardrails, which can be designed to give the appropriate balance between the capacity to deflect a nearly head-on vehicle back to its right-of-way and the capacity to buckle sufficiently that penetration of the vehicle may be averted.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1065-1070
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• 2006

The beam structure models with an impactor or contact parts under impact forces have teen applied to the design of mechanical and electronic accessories. Switches, hard-disk pick-ups and sensors are typical structural examples of the structure to be designed to colliding with other parts of structures. In this paper, in order to examine the relationships between the changes of the stiffness and damping of the impactor and vibrations of the dynamic characteristics of the impact model of a cantilevered beam with an impactor, impact force of the impactor and response characteristics of the cantilevered beam were analyzed by both numerical simulation and experiment. Since the stiffness and damping of the impactor have high nonlinear characteristics, the contact model using revised Herz-model was established by experiments. Also, the results of numerical analyses for dynamic response and impact force of a cantilevered beam with an impactor have a good agreement with experimental results.