نتایج جستجو برای: frequencies of vibration

تعداد نتایج: 21171501  

Journal: :Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2008
Juha Kiiski Ari Heinonen Teppo L Järvinen Pekka Kannus Harri Sievänen

According to experimental studies, low-amplitude high-frequency vibration is anabolic to bone tissue, whereas in clinical trials, the bone effects have varied. Given the potential of whole body vibration in bone training, this study aimed at exploring the transmission of vertical sinusoidal vibration to the human body over a wide range of applicable amplitudes (from 0.05 to 3 mm) and frequencie...

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...

Journal: :international journal of advanced design and manufacturing technology 0
farzad ebrahimi abbas rastgoo

in this paper, a nonlinear free vibration analysis of thin annular functionally graded (fg) plate integrated with two uniformly distributed actuator layers made of piezoelectric (pzt4) material on the top and bottom surfaces of the annular fg plate is presented based on kirchhoff plate theory. the material properties of the fgm core plate are assumed to be graded in the thickness direction acco...

2001
William Wei

The wide application of switched reluctance motors (SRM) is limited by their higher vibration and acoustic noise. An accurate determination of resonant frequencies and mode shapes of the SRM stator is therefore essential for low acoustic noise design. Based on the structural finite element method and elasticity theory, 3D vibration modes and resonant frequencies of a 5 hp SRM with 8/6 poles are...

Journal: :Physiological research 2001
A Polónyová F Hlavacka

We analyzed human postural responses to muscle vibration applied at four different frequencies to lower leg muscles, the lateral gastrocnemius (GA) or tibialis anterior (TA) muscles. The muscle vibrations induced changes in postural orientation characterized by the center of pressure (CoP) on the force platform surface on which the subjects were standing. Unilateral vibratory stimulation of TA ...

In this article, using generalized differential quadrature (GDQ) methods, free vibration of a thin annular plate coupled with two open circuit piezoelectric layers, is numerically studied based on the classical plate theory. The governing differential equations with respective boundary conditions are derived and transformed into a set of algebraic equations by implementing the GDQ rule, then so...

Journal: :Industrial health 2010
Miyuki Morioka Michael J Griffin

Fore-and-aft vibration of a backrest can influence discomfort and the risk of injury associated with whole-body vibration. Relevant standards (BS 6841:1987 and ISO2631-1:1997) recommend the W(c) frequency weighting for evaluating fore-and-aft vibration of backrests, but do not specify the precise location for measuring vibration. This study determined equivalent comfort contours for fore-and-af...

Journal: :نشریه دانشکده فنی 0
دکتر یوسف حسن زاده

it has been proved that natural frequencies are stationary at the natural modes. also it has been shown that at the first mode it is a minimum and for systems with finite number of degrees of freedom the highest frequency is maximum (reference 1 and 2). beyond these statements nothing more can be said about the behavior of the natural frequencies without defining precisely the manner in which t...

2005
T. Maeda Y. Sugiura T. Hirai

Bayon temple, Angkor, built in the late 12th century to the early 13th century, is a masonry temple made of sandstone which has deteriorated possibly due to rain, plants, settlements, and so on. Strong winds blowing more than 20m/sec were observed in the rainy season, which may cause vibration of the structure either directly or via ground motion, we may add wind induced vibration to the list o...

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