نتایج جستجو برای: vibration stress

تعداد نتایج: 487237  

2013
JIHUI LIANG LILI XIN

Internal friction and void ratio will change among granular particles under vibration, and the size of void ratio directly affects strength of granular media. To further study the effect of vibration parameters on granular mechanical properties, discrete element method is used to simulate particles motion in a vibrating rectangular case by PFC2D software and study the influence of vibration fre...

Journal: :journal of ultrafine grained and nanostructured materials 2015
hessam rouhi reza ansari mansour darvizeh

it has been revealed that the surface stress effect plays an important role in the mechanical behavior ofstructures (such as bending, buckling and vibration) when their dimensions are on the order ofnanometer. in addition, recent advances in nanotechnology have proposed several applications fornanoscale shells in different fields. hence, in the present article, within the framework of surfaceel...

Journal: :Nanotechnology 2012
Javier Tamayo Valerio Pini Prisicila Kosaka Nicolas F Martinez Oscar Ahumada Montserrat Calleja

There is a need for noninvasive techniques for simultaneous imaging of the stress and vibration mode shapes of nanomechanical systems in the fields of scanning probe microscopy, nanomechanical biological and chemical sensors and the semiconductor industry. Here we show a novel technique that combines a scanning laser, the beam deflection method and digital multifrequency excitation and analysis...

Journal: :Microelectronics Reliability 2009
F. X. Che John H. L. Pang

Vibration fatigue test and analysis methodology for flip chip solder joint fatigue life assessment have been developed by performing vibration tests with constant G-level and varying G-level input excitation. The linear cumulative damage analysis method (Miner’s rule) predicts non-conservative result for vibration fatigue life of flip chip solder joint. Finite element analysis (FEA) using a glo...

2017
Hongfang Lu

Due to the periodic movement of the piston in the reciprocating pump, the fluid will cause 8 pressure pulsation, and the vibration of the pipeline will lead to instrument distortion, pipe failure 9 and equipment damage. Therefore, it is necessary to study the vibration phenomena of the 10 reciprocating pump pipeline based on the pressure pulsation theory. This paper starts from the 11 reciproca...

2016
Liping Wang Hung-Yao Hsu Xu Li Cory J Xian

Bone cells are deformed according to mechanical stimulation they receive and their mechanical characteristics. However, how osteoblasts are affected by mechanical vibration frequency and acceleration amplitude remains unclear. By developing 3D osteoblast finite element (FE) models, this study investigated the effect of cell shapes on vibration characteristics and effect of acceleration (vibrati...

2014
L. Gerhardsson M. Hagberg

BACKGROUND Hand-arm vibration exposure may cause hand-arm vibration syndrome (HAVS) including sensorineural disturbances. AIMS To investigate which factors had the strongest impact on work ability in vibration-exposed workers. METHODS A cross-sectional study in which vibration-exposed workers referred to a department of occupational and environmental medicine were compared with a randomized...

2005
H Cai

Based on Timoshenko laminated beam models, this paper investigates the influence of initial stress on the vibration and transverse wave propagation in individual multi-wall carbon nanotubes (MWNTs) under ultrahigh frequency (above 1 THz), in which the initial stress in the MWNTs can occur due to thermal or lattice mismatch between different materials. Considering van der Waals force interaction...

In this paper, a numerical solution procedure is presented for the free and forced vibration of a piezoelectric nanowire under thermo-electro-mechanical loads based on the nonlocal elasticity theory within the framework of Timoshenko beam theory. The influences of surface piezoelectricity, surface elasticity and residual surface stress are taken into consideration. Using Hamilton’s principle, t...

Journal: :international journal of advanced design and manufacturing technology 0
farzad ebrahimi faculty of engineering, imam khomeini international university gholam reza shaghaghi department of mechanical engineering, university of imam khomeini international, iran

abstract: in this paper, nonlocal euler–bernoulli beam theory is employed for transverse vibration analysis of an initially pre-stressed size-dependent rotating nanotube. the nonlocal eringen theory takes into account the effect of small size, which enables the present model to become effective in the analysis and design of nanosensors and nanoactuators. governing equations are derived through ...

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