• Earthquakes and Structures
• /
• 제18권3호
• /
• pp.313-320
• /
• 2020

The usage of conventional tuned mass damper (TMD) was proved as an effective method for passive mitigating vortex-induced vibration (VIV) of a bridge deck. Although a variety of linear TMD systems have been so far utilized for vibration control of suspension bridges, a sensitive TMD mechanism to wind spectrum frequency is lacking. Here, we introduce a bistable tuned mass damper (BTMD) mechanism which has an exceptional sensitivity to a broadband input of vortex shedding velocity for suppressing VIV in suspension bridge deck. By use of the Monte Carlo simulation, performance of the nonlinear BTMD is shown to be more efficient than the conventional linear TMD under two different wind load excitations of harmonic (sinusoidal) and broadband input of vortex shedding. Consequently, an appropriate algorithm is proposed to optimize the design parameters of the nonlinear BTMD for Kap Shui Mun Bridge, and then the BTMD system is localized for the interior deck of the suspension bridge.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1995년도 춘계학술대회논문집; 전남대학교, 19 May 1995
• /
• pp.18-21
• /
• 1995

A numerical method is presented to obtain natural frequencies and mode shapes of the arbitrary tapered beams with static deflections due to arbitrary distributed dead loads. The differential equation governing the free vibration is derived and solved numerically. In the numerical example, the linearly tapered beams and both the triangular and sinusoidal distributed dead loads are chosen. The lowest three natural frequencies are reported and typical mode shapes are presented in the figure.

• 한국소음진동공학회논문집
• /
• 제20권2호
• /
• pp.144-152
• /
• 2010

This paper deals with free vibrations of the tapered circular arches with constant volume, whose cross sectional shape is the solid regular polygon. Volumes of the objective arches are always held constant regardless shape functions of the cross-sectional depth. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such arches are derived and solved numerically for determining the natural frequencies. In the numerical examples, hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, the relationships between non-dimensional frequency parameters and various arch parameters such as rise ratio, section ratio, side number, volume ratio and taper type are reported in tables and figures.

• 한국소음진동공학회논문집
• /
• 제21권6호
• /
• pp.570-579
• /
• 2011

This paper deals with free vibrations of the circular curved beams with constant volume, whose cross sectional shapes are the circular solid cross-sections. Volumes of the objective beam are always held in constant regardless shape functions of the cross-sectional radius. The shape functions are chosen as the linear, parabolic and sinusoidal ones. Ordinary differential equations governing free vibrations of such beam are derived and solved numerically for determining the natural frequencies. In numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. As the numerical results, relationships between frequency parameters and various beam parameters such as rise ratio, section ratio, elasticity ratio, volume ratio, slenderness ratio and taper type are reported in tables and figures.

• 한국안전학회지
• /
• 제15권1호
• /
• pp.1-10
• /
• 2000

This paper deals with rocking response behavior of rigid block structure subjected to horizontal excitation. A strict consideration of impact and sliding between the block and base is essential to investigate the rocking vibration characteristics because the rocking behavior were greatly influenced by the impact and sliding motion. Therefore, not only restitution coefficient between the block and base but also the energy dissipation rate which is associated with sliding motion, and the static and kinetic friction coefficient between those should be included in the modeling of rocking system. The analytic program was developed to be able to simulate the experimental responses of the block subjected to horizontal sinusoidal excitations. By using this program, rocking responses were numerically calculated by the nonlinear equations for rocking system. From the response simulation and rocking vibration experiment, the following results were obtained. The rocking responses are affected by the impact motion due to energy dissipation and friction and provide very complex behavior. The toppling condition of the block is also influenced by the impact motion and sliding motion.

• Smart Structures and Systems
• /
• 제19권4호
• /
• pp.441-448
• /
• 2017

This paper uses the four-variable refined plate theory for the free vibration analysis of functionally graded material (FGM) rectangular plates. The plate properties are assumed to be varied through the thickness following a simple power law distribution in terms of volume fraction of material constituents. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Equations of motion are derived from the Hamilton's principle. The closed-form solutions of functionally graded plates are obtained using Navier solution. Numerical results of the refined plate theory are presented to show the effect of the material distribution, the aspect and side-to-thickness ratio on the fundamental frequencies. It can be concluded that the proposed theory is accurate and simple in solving the free vibration behavior of functionally graded plates.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2008년도 추계학술대회A
• /
• pp.502-507
• /
• 2008

An entire composite structure satellite is developing for the first time in Korea. All of the structure is made of CFRP-composite faced aluminum honeycomb sandwich structure. Here the random and sinusoidal spectrum analysis of the satellite was carried out by using the finite element method. The general spectrum analysis was herein performed but also the PSD (power spectrum density) function for random vibration analysis had been transformed into equivalent time domain function and then transient analysis is conducted. The time history of displacement, acceleration, stress and velocity responses with respect to the PSD input has been achieved by the time dependent transient function transformed from frequency PDS function. It enables one to perform dynamic durability analysis and then expect the life time of the composite structure. The composite faced sandwich structure's spectrum analysis of a domestically-developed satellite, STSAT-3, has been discussed in the present study.

• 한국생산제조학회지
• /
• 제7권3호
• /
• pp.7-13
• /
• 1998

This paper presents a new concept of a commercial vehicle seat suspension system. The proposed suspension system features an ER(electro-rheological)damper which can produce continuously tunable damping forces by control elecric fields. A dynamic model of the ER damper is first achieved by incorporating Bingham property of the ER fluid, followed by the formulation of governing equations of motion for the suspension system The effectiveness of the proposed ER seat suspension system is evaluated by investigating vibration with respect to sinusoidal inputs.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 춘계학술대회논문집
• /
• pp.417-422
• /
• 2002

The main purpose of this paper is to determine the dynamic optimal shapes of tapered column with constant volume. The linear, parabolic and sinusoidal tapers with the regular polygon cross-section are considered, whose material volume and span length are always held constant. The ordinary differential equation including the effect of axial load is applied to calculate the natural frequencies. The Runge-Kutta method and Regula-Falsi methods are used to integrate the differential equation and compute the frequencies, respectively. Then the dynamic optimal shape whose lowest natural frequency is highest is determined by reading the critical value of the frequency versus section ratio curve plotted by the frequency data. In the numerical examples, the tapered columns are analysed and the numerical result of this study are shown in table and figures.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2014년도 추계학술대회 논문집
• /
• pp.72-74
• /
• 2014

Multilayer ceramic capacitor (MLCC) makes acoustic noise of electronic devices. Conversed piezoelectric effect of dielectric substance consists of $BaTiO_3$ causes vibration of MLCC so it must be analyzed to reduce the noise. Thus, finite element model for piezoelectric analysis of MLCC was constructed in this paper. Piezoelectric characteristics of MLCC was considered for the accurate simulation result. Displacement response for sinusoidal voltage signal was measured and simulation result was verified with test result.