نتایج جستجو برای: vibration mode

تعداد نتایج: 269836  

2013
Jingyu Yang Guoping Chen

Abstract: In this paper, we developed an approach for active vibration control of flexible rectangular plate structures using control theory. The flexible rectangular plate system is firstly modelled and simulated via a finite element method; and secondly, a new type of modelling method, and the state-space model are involved in the development of the equation of motion in state-space, which is...

Journal: :Dental materials journal 2007
Yukio Kojima Hisao Fukui

Natural frequencies and vibration modes of four kinds of teeth were calculated by using a mechanical model. The alveolar bone and the tooth were assumed as rigid bodies, while the periodontal ligament was assumed as an elastic spring. All the natural frequencies were within a range of 1 to 10 kHz. The first natural frequencies of four teeth were about 1.5 kHz, and decreased as the root length d...

2014
David Camarena-Martinez Juan P Amezquita-Sanchez Martin Valtierra-Rodriguez Rene J Romero-Troncoso Roque A Osornio-Rios Arturo Garcia-Perez

This paper presents a new EEMD-MUSIC- (ensemble empirical mode decomposition-multiple signal classification-) based methodology to identify modal frequencies in structures ranging from free and ambient vibration signals produced by artificial and natural excitations and also considering several factors as nonstationary effects, close modal frequencies, and noisy environments, which are common s...

2001
Jan Holterman Theo J.A. de Vries

A self-tuning procedure is proposed for an active structural element with collocated sensing and actuation (a so-called ‘Smart Disc’). The procedure aims at optimal active damping by means of Integral Force Feedback control. In case the behavior of the structure to be damped may be described by a single dominant vibration mode, self-tuning is realized in two fairly simple steps: (1) recursive e...

ذاکریان, ابوالفضل, رفیعی پور, آتنا, محمدیان, فاروق, منظم اسماعیل پور, محمد رضا, نصیری, پروین, گیاهی, امید,

Introduction: Exposure to vibration as one of the consequences of industrial noise or the use of vibration generators can cause discomfort, reduce the efficiency and level of safety in workplaces. Therefore, in this study, the effect of whole body vibration on individual’s mental performance and response time was investigated. Material and Method: In this study, 40 male students of Tehran Un...

H Zohoor, M.H Kargarnovin N.S Viliani,

This paper presents the dynamic modeling and design of micro motion compliant parallel mechanism with flexible intermediate links and rigid moving platform. Modeling of mechanism is described with closed kinematic loops and the dynamic equations are derived using Lagrange multipliers and Kane’s methods. Euler-Bernoulli beam theory is considered for modeling the intermediate flexible link. Based...

2017
Zengguang Qin Hui Chen Jun Chang

We propose a novel denoising method based on empirical mode decomposition (EMD) to improve the signal-to-noise ratio (SNR) for vibration sensing in phase-sensitive optical time domain reflectometry (φ-OTDR) systems. Raw Rayleigh backscattering traces are decomposed into a series of intrinsic mode functions (IMFs) and a residual component using an EMD algorithm. High frequency noise is eliminate...

2015
A. Mathieson

The design of slender power ultrasonic devices can often be challenging due to the excitation of parasitic modes of vibration during operation. The excitation of these modes is known to manifest from behaviors such as modal coupling which if not controlled or designed out of the system can, under operational conditions, lead to poor device performance and device failure. However, a report publi...

Journal: :journal of solid mechanics 0
f saljughi national iranian oil company (nioc), iran

a finite element analysis is presented for sloshing and impulsive motion of liquid-filled conical tanks during lateral anti-symmetric excitation. the performed analyses led to the development of a number of charts which can be used to identify the natural frequency, the mode shapes of conical tanks for both fundamental and the cos(θ)-modes of vibration. conical tank geometry was described with ...

A Rastgoo M Soleimani M.H Amini,

This paper deals with the nonlinear free vibration of thick annular functionally graded material plates. The thickness is assumed to be constant. Material properties are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. The formulations are based on the first-order shear deformation plate theory and...

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