• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1321-1324
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• 2007

In this paper, the in-plane end vibration of a cylindrical shell has been analyzed. The theoretical result has showed that the strong in-plane vibration at the ends of the cylindrical shell can be generated by the evanescent wave field, which is excited along about half the length of the shell. This has been also observed from experimental result. The evanescent waves are generated due to mode conversion of elastic waves at the ends of the cylindrical shells. The results show that the strong in-plane end vibration can be generated in cylindrical shells.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.190-197
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• 2002

A new design methodology is presented for the multi-degree-of-freedom vibration absorber for an elastically suspended rigid body with planes of symmetry in general motion. Unlike the common single degree-of-freedom vibration absorber, the presented methodology makes use of both linear and rotational properties of the absorber. It is suggested that an absorber is designed separately for the in-plane and out-of-plane vibration modes and thereby combined the two cases for a six-degree-of-freedom absorber. The nine possible design methods are suggested for the six-degree-of-freedom absorber when an elastically suspended rigid body has one, two, or three planes of symmetry.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.325.2-325
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• 2002

A new methodology is presented for the multi-degree-of-freedom vibration absorber for an elastically suspended rigid body with the planes of symmetry in general motion. Unlike the common single degree-of-freedom vibration absorber, the presented methodology makes use of both linear and rotational properties of the absorber. It is suggested that an absorber is designed separately for the in-plane and out-of-plane axes of vibration and combined the two cases for a six-degree-of-freedom absorber. (omitted)

• 대한건축학회논문집:구조계
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• 제35권9호
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• pp.171-182
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• 2019

Isogeometric concept is introduced to carry out free vibration analysis of plane structures. The geometry of structures is represented by using non-uniform rational B-spline surface (NURBS) and its basis function is consistently used in the formulation of plane stress element. In addition, multi-patch strategy is introduced to deal with the openings in building. The performance of the present isogeometric plane stress element is investigated by using five numerical examples. From numerical results, it is found to be that the isogeometric concept can successfully identify reliable natural frequencies and associated mode shapes of plane structures with/without openings in efficient way.

• 한국음향학회지
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• 제24권7호
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• pp.371-378
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• 2005

본 연구에서는 면내 진동하는 감쇠 단을 갖는 보에서 진동파워의 크기와 방향을 나타내는 면내 진동인텐시티를 측정하였다. 보의 면내 진동인텐시티 측정 방법으로서 3가지 다양한 방법을 적용하였다. 이러한 방법들은 2개의 가속도계 선형 배열을 이용하는 가속도계배열법과 하나의 가속도계를 갖고 주파수응답함수를 이용하는 주파수응답함수법 그리고 기준 가속도를 고정시키고 다른 하나의 가속도계를 이용하는 기준가속도계법 들이다. 본 연구에서는 이러한 방법들을 적용하여 보의 진동인텐시티 공간 분포를 측정하여 비교하였으며, 또한 가진 점에서 주어지는 입력 파워와 비교를 통하여 적용 가능성을 확인하였다. 이러한 결과들로부터 보의 면내 진동인텐시티를 측정하기 위하여 가속도계배열법뿐만이 아니라 주파수응답함수법과 기준가속도계법 또한 효과적으로 사용될 수 있음을 보였다.

• 대한기계학회논문집A
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• 제27권1호
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• pp.42-47
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• 2003

Nonlinear models for a thin ring rotating at a constant speed are developed. The geometric nonlinearity of displacements is considered by adopting the Lagrange strain theory for the circumferential strain. By using Hamilton’s principle, the coupled nonlinear partial differential equations are derived, which describe the out-of-plane and in-plane bending, extensional and torsional motions. The natural frequencies are calculated from the linearized equations at various rotational speeds. Finally, the computation results from the nonlinear models are compared with those from a linear model. Based on the comparison, this study recommends which model is appropriate to describe the behavior of the rotating ring.

• 한국공간구조학회논문집
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• 제4권4호
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• pp.99-111
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• 2004

An exact solution procedure is formulated for the free vibration and buckling analysis of rectangular plates having two opposite edges simply supported when these edges are subjected to linearly varying normal stresses. The other two edges may be clamped, simply supported or free, or they may be elastically supported. The transverse displacement (w) is assumed as sinusoidal in the direction of loading (x), and a power series is assumed in the lateral (y) direction (i.e., the method of Frobenius). Applying the boundary conditions yields the eigenvalue problem of finding the roots of a fourth order characteristic determinant. Care must be exercised to obtain adequate convergence for accurate vibration frequencies and buckling loads, as is demonstrated by two convergence tables. Some interesting and useful results for vibration frequencies and buckling loads, and their mode shapes, are presented for a variety of edge conditions and in-plane loadings, especially pure in-plane moments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.521-525
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• 2004

This paper has the object of investigating natural frequencies of tapered thick plate on pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. vibration analysis that tapered thick plate subjected to In-plane stress is presented in this paper Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. In order to analysis tapered plate which is supported on pasternak foundation. The ratio of In-plane stress to critical load is varied with $0.2\sigma_{cr},\;0.4\sigma_{cr},\;0.6\sigma_{cr}$, and the Winkler parameter is 0, 10, 100, 1000 the shear foundation parameter 0, 10. The taper ratio is applied as 0.0, 0.2, 0.4, 0.6, 0.8 respectively. This paper is analyzed varying thickness by taper ratio with In-plane stress.

• 대한기계학회논문집A
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• 제24권1호
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• pp.110-117
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• 2000

Vibration modes obtained from a modal analysis can be better explained from a screw theoretical standpoint. A vibration mode can be geometrically interpreted as a pure rotation about the vibration center in a plane and as the twisting motion on a screw in a three dimensional space. This paper, presents the method to diagonalize a spatial stiffness matrix by use of a parallel axis congruence transformation. It also describes that the stiffness matrix diagonalized by a congruence transformation, can have the planes of symmetry depending on the location of the center of elasticity. For a plane of symmetry, any vibration mode can be expressed by the axis of vibration. Analytical solutions for the axis of vibration has been derived.

• Structural Engineering and Mechanics
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• 제59권3호
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• pp.503-526
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• 2016

In-plane and out-of-plane free vibration analysis of Timoshenko curved beams is addressed based on the isogeometric method, and an effective scheme to avoid numerical locking in both of the two patterns is proposed in this paper. The isogeometric computational model takes into account the effects of shear deformation, rotary inertia and axis extensibility of curved beams, and is applicable for uniform circular beams, and more complicated variable curvature and cross-section beams as illustrated by numerical examples. Meanwhile, it is shown that, the $C^{p-1}$-continuous NURBS elements remarkably have higher accuracy than the finite elements with the same number of degrees of freedom. Nevertheless, for in-plane or out-of-plane vibration analysis of Timoshenko curved beams, the NURBS-based isogeometric method also exhibits locking effect to some extent. To eliminate numerical locking, the selective reduced one-point integration and $\bar{B}$ projection element based on stiffness ratio is devised to achieve locking free analysis for in-plane and out-of-plane models, respectively. The suggested integral schemes for moderately slender models obtain accurate results in both dominated and non-dominated regions of locking effect. Moreover, this strategy is effective for beam structures with different slenderness. Finally, the influence factors of structural parameters of curved beams on their natural frequency are scrutinized.