• Title/Summary/Keyword: Longitudinal Vibration Mode

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Forced vibration of nanorods using nonlocal elasticity

  • Aydogdu, Metin;Arda, Mustafa
    • Advances in nano research
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    • v.4 no.4
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    • pp.265-279
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    • 2016
  • Present study interests with the longitudinal forced vibration of nanorods. The nonlocal elasticity theory of Eringen is used in modeling of nanorods. Uniform, linear and sinusoidal axial loads are considered. Dynamic displacements are obtained for nanorods with different geometrical properties, boundary conditions and nonlocal parameters. The nonlocal effect increases dynamic displacement and frequency when compared with local elasticity theory. Present results can be useful for modeling of the axial nanomotors and nanoelectromechanical systems.

Finite strain nonlinear longitudinal vibration of nanorods

  • Eren, Mehmet;Aydogdu, Metin
    • Advances in nano research
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    • v.6 no.4
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    • pp.323-337
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    • 2018
  • The nonlinear free vibration of a nanorod subjected to finite strain is investigated. The governing equation of motion in material configuration in terms of displacement is determined. By means of Galerkin method, the Fourier series solutions satisfying some typical boundary conditions are determined. The amplitude-frequency relationship and interaction between the modes are studied. The effects of nonlocal elasticity are shown for different length of nanotubes and nonlocal parameter. The results show that nonlocal effects lead to additional internal modal interaction for nanorod vibrations.

Influence of structural system measures on the dynamic characteristics of a multi-span cable-stayed bridge

  • Geng, Fangfang;Ding, Youliang;Xie, Hongen;Song, Jianyong;Li, Wanheng
    • Structural Engineering and Mechanics
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    • v.52 no.1
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    • pp.51-73
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    • 2014
  • A three-dimensional finite element model for the Jiashao Bridge, the longest multi-span cable-stayed bridge in the world, is established using the commercial software package ANSYS. Dynamic characteristics of the bridge are analyzed and the effects of structural system measures including the rigid hinge, auxiliary piers and longitudinal constraints between the girders and side towers on the dynamic properties including modal frequency, mode shape and effective mass are studied by referring to the Jiashao Bridge. The analysis results reveal that: (i) the installation of the rigid hinge significantly reduces the modal frequency of the first symmetric lateral bending mode of bridge deck. Moreover, the rigid hinge significantly changes the mode shape and effective mass of the first symmetric torsional mode of bridge deck; (ii) the layout of the auxiliary piers in the side-spans has a limited effect on changing the modal frequencies, mode shapes and effective masses of global vibration modes; (iii) the employment of the longitudinal constraints significantly increases the modal frequencies of the vertical bending modes and lateral bending modes of bridge deck and have significant effects on changing the mode shapes of vertical bending modes and lateral bending modes of bridge deck. Moreover, the effective mass of the first anti-symmetric vertical bending of bridge deck in the longitudinal direction of the fully floating system is significantly larger than that of the partially constrained system and fully constrained system. The results obtained indicate that the structural system measures of the multi-span cable-stayed bridge have a great effect on the dynamic properties, which deserves special attention for seismic design and wind-resistant design of the multi-span cable-stayed bridge.

Condensation of independent variables in free vibration analysis of curved beams

  • Mochida, Yusuke;Ilanko, Sinniah
    • Advances in aircraft and spacecraft science
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    • v.3 no.1
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    • pp.45-59
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    • 2016
  • In this paper, the condensation method which is based on the Rayleigh-Ritz method, is described for the free vibration analysis of axially loaded slightly curved beams subject to partial axial restraints. If the longitudinal inertia is neglected, some of the Rayleigh-Ritz minimization equations are independent of the frequency. These equations can be used to formulate a relationship between the weighting coefficients associated with the lateral and longitudinal displacements, which leads to "connection coefficient matrix". Once this matrix is formed, it is then substituted into the remaining Rayleigh-Ritz equations to obtain an eigenvalue equation with a reduced matrix size. This method has been applied to simply supported and partially clamped beams with three different shapes of imperfection. The results indicate that for small imperfections resembling the fundamental vibration mode, the sum of the square of the fundamental natural and a non-dimensional axial load ratio normalized with respect to the fundamental critical load is approximately proportional to the square of the central displacement.

Development and Experimentation of a Non-Contact Magnetostrictive Sensor for the Elastic Wave Mode Selection (탄성파의 선택적 측정을 위한 비접촉 마그네토스트릭션 센서의 개발 및 실험적 검증)

  • 김영규;이호철;김윤영
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.549-553
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    • 2002
  • Although the magnetostrictive sensors have received much attention in recent years. the investigations on the selection of a desired mode have not been reported. The purpose of this investigation is to present a technique to select a desired mode in a solid ferromagnetic cylinder using a non-contact magnetostrictive sensor. To achieve this goal. we propose new bias magnet configurations to select longitudinal and flexural waves. A few experimental results confirm the validity of the present investigation.

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Design and Trial Fabrication of Plate-Type Linear Ultrasonic Motor Using L1-B4 Vibration Mode (L1-B4 진동모드를 이용한 평판형 선형 초음파 모터의 설계 및 시제작)

  • 이종섭;정수현;임기조;임태빈;강성택;채홍인
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.10
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    • pp.861-865
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    • 1998
  • A plate-type linear ultrasonic motor using logitudinal and bending multi-vibration mode was designed and fabricated for the application to card-forwarding device. The stator consisted of PZ-PT-PMS piezoelectric ceramic plate and stainless steel. The performances of the motor were measured. As the experimental results, no-load speed of the motor was 0.6m/s when applied voltage was $80\textrm{V}_{rms}$ in resonance frequency. Starting torque was 1.4 mNm and maximum efficiency was 1.2%.

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A Study on a Ultrasonic Vibration Assisted Grinding of Alumina Ceramic with Diamond Grinding Tool (초음파 진동을 하는 다이아몬드 연삭공구의 알루미나 세라믹 연삭 가공에 관한 연구)

  • Choi, Young-Jae;Song, Ki-Hyeong;Park, Kyung-Hee;Hong, Yun-Hyuck;Kim, Kyeong-Tae;Lee, Seok-Woo;Choi, Hon-Zong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.1
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    • pp.13-19
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    • 2012
  • In this study, ultrasonic vibration tool designed and made by using FEM analysis. And machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic ($Al_2O_3$) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20kHz was generated by HSK 63 ultrasonic actuator. The two grinding speeds, 1.67m/s and 3.35m/s, were applied. On the other hand, grinding forces were measured by KISTLER dynamometer.

Free Vibrations of Horizontally Curved Beams with Multiple Elastic Springs (여러 개의 스프링으로 탄성 지지된 수평 곡선보의 자유진동)

  • 이병구;진태기;최규문;이태은
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.5
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    • pp.101-107
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    • 2001
  • This paper deals with the free vibrations of horizontally curved beams with mu1tiple elastic springs. Taking into account the effects of rotatory Inertia and shear deformation. differential equations governing the free vibrations of such beams are derived, In which each e1astic spring is modeled as a discrete Winkler foundation with very short longitudinal length. Differential equations are solved numerically to calculate natural frequencies and mode shapes. In numerical examples, the circular, Parabolic. sinusoidal and elliptic curved beams are considered. The parametric studies are conducted and the lowest four frequency parameters are reported In tables and figures as the non-dimensional forms. Also the typical mode shapes are presented.

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Design of Ultrasonic Vibration Tool Horn for Micromachining Using FEM (유한요소법을 이용한 초음파 진동 공구혼 설계에 관한 연구)

  • Lee, Bong-Gu;Kim, Kwang-Lae;Kim, Kang-Eun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.63-70
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    • 2008
  • Conical horn is used in many high frequency ultrasonic horns, to achieve a longitudinal vibration mode across a wide ultrasonic tool horn output surface. Modal analysis is method for designing tuned ultrasonic tool horn and for the prediction natural frequency of ultrasonic tool horn vibration mode. The design of ultrasonic horn is based on prototype estimate obtained by FEM analysis. The FEM simulated ultrasonic tool horn is built and characterized experimentally through laser vibrometer and electrical impedance analysis. In this paper, FEM analysis is developed to predict the natural frequency of ultrasonic tool horn and use of in the optimal design of ultrasonic horn shape.

Prediction of Crack Initiation and Design of 40kHz Blade Horn for Ultrasonic Cutting (40kHz 초음파 커팅용 혼의 설계와 크랙발생에 대한 고찰)

  • Seo, Jeong-Seok;Lee, Yoon-Jung;Beak, Si-Young;Park, Dong-Sam
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.5
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    • pp.784-789
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    • 2012
  • Ultrasonic Cutting which uses a tuned blade resonant in a longitudinal mode, has been used to cut a range of materials from confectionery, baked products and frozen foods, to wood, bone, foams and composites. The Blade design typically uses finite element analysis, and it could be predicted vibration mode, gain and amplitude uniformity of the blade tip at resonant frequency. In this paper, FEA used to predict the vibration characteristic of the blade, and then the results were verified by analysis system of resonant frequency using the processed blade. The crack of the blade which is predicted from FEA was compared with the crack occurred by cutting experiment of rubber materials using the processed blade.