• Coupled systems mechanics
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• v.5 no.3
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• pp.235-254
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• 2016

A numerical model for fluid-structure interactions (abbr. FSI) is presented in the context of sloshing effects in movable, partially filled tanks to improve understanding of interactions between the fluid and the dynamics of a tank flexibly attached to a vehicle. The purpose of this model is to counteract the penalizing impact of the added mass effect on classical partitioned FSI coupling scheme: the proposed investigation is based on an added mass corrected version of the classical strongly coupled partitioned scheme presented in (Song et al. 2013). Results show that this corrected version systematically allows convergence to the coupled solution. In the rare cases where convergence is already obtained, the corrected version significantly reduces the number of iterations required. Finally, it is shown that the convergence limit imposed by added mass effect for the non-corrected coupling scheme, is directly dependent on the aspect ratio of the fluid domain and highly related to the precision order of the temporal discretization scheme.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.322-323
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• 2003

Silicon substrate was fabricated by bulk silicon micromachining and it's structure is based on a proof mass suspended by two beam. To monitor the acceleration, dynamic excitation of accelerometer was performed using a shaker. The attached FFPI and suspension beam are bent because support beam move with variation of the proof mass. Thus phase difference detected by the acceleration change. So we can know that resonance frequency of fabricated accelerometer is about 557 Hz and dynamic range was measured from 0 g to 2 g.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1815-1823
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• 2003

The vibrational system of this study consists of a cantilever pipe conveying fluid, the moving masses upon it and having an attached tip mass. The equation of motion is derived by using Lagrange's equation. The influences of the velocity and the inertia force of the moving mass and the velocities of fluid flow in the pipe have been studied on the dynamic behavior and the natural frequency of a cantilever pipe by numerical method. The deflection of the cantilever pipe conveying fluid is increased due to the tip mass and rotary Inertia. After the moving mass passed upon the cantilever pipe, the amplitude of pipe is influenced by energy variation when the moving mass fall from the cantilever pipe. As the moving mass increase, the frequency of the cantilever pipe conveying fluid is increased. The rotary inertia of the tip mass influences much on the higher frequencies and vibration mode.

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.216-219
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• 2005

In this study, we will explain the design, test results and analysis of system for measuring the small mass in the microgravity environment. It is so difficult to measure the mass by sensing the gravity as the ground in the microgravity environment. The suggested method is to measure the resonance frequency of a sample. The resonance frequency may be measured as a function of mass. If we know the resonance frequency of the mass, we can guess the mass by detecting the resonance frequency. Piezoelectric ceramics have the characteristics that resonance frequency is changed by total mass which are its mass and the attached mass. This system have some problems but we verified that we can measure the unknown mass using the resonance frequency as the mass.

• Journal of KSNVE
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• v.3 no.1
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• pp.57-63
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• 1993

The dynamic response of stiffened rectangular plate subjected to a concentrated force or mass moving at constant speed is analyzed by using finite- element method. Stiffened plates are modelled as an assembly of isotropic thin plate elements and equivalent Euler beam ones, in which the beam elements represent the stiffener effects concentrated at the attached lines of stiffeners to the plates. The Newmark's time integration method is used to obtain the dynamic response of stiffened plates. Numerical examples are given to verify the validity of the presented method and also to investigate the effects of speed and moving mass on the dynamic characteristics of stiffened plates.

• Archives of Plastic Surgery
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• v.38 no.1
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• pp.117-120
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• 2011

Purpose: Carpal tunnel syndrome is the most common peripheral compressive neuropathy. Most cases are idiopathic, but rarely carpal tunnel syndrome can be associated with a ganglionic mass. We report our recently encountered experience of surgical treatment of carpal tunnel syndrome caused by a simple ganglionic mass. Methods: A 53-year-old man presented with chief complaints of numbness and hypoesthesia of his left palm, thumb, index finger, long finger, and ring finger of one and half month duration. Physical examination revealed positive Tinnel's sign without previous trauma, infection or any other events. Electromyography showed entrapment neuropathy of the median nerve. Magnetic resonance imaging (MRI) showed an approximately 2.0 cm-sized mass below the transverse carpal ligament. Upon surgical excision, a $1{\times}1.5cm^2$ mass attached to the perineurium of the median nerve and synovial sheath of the flexor digitorum superficialis and redness and hypertrophy of the median nerve were discovered. With surgical intervention, we completely removed the ganglionic mass and performed surgical release of the transverse carpal ligament. Results: The pathology report confirmed the mass to be a ganglion. The patient exhibited post-operative improvement of his symptoms and did not show any complications. Conclusion: We present a review of our experience with this rare case of carpal tunnel syndrome caused by a ganglionic mass and give a detailed follow-up on the patient treated by surgical exploration with carpal tunnel release.

• Journal of Ocean Engineering and Technology
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• v.16 no.6
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• pp.18-24
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• 2002

The vibrational system in this study consists of a cantilever pipe conveying fluid, the moving mass upon it, and an attached tip mass. The equation of motion is derived by using the Lagrange equation. The influences of the velocity and the velocities of fluid flow in the pipe have been studied on the dynamic behavior of a cantilever pipe using a numerical method. While the moving mass moves upon the cantilever pipe, the velocity of fluid flow and the nozzle angle increase; as a result, the tip displacement of the cantilever pipe, conveying fluid, is decreased. After the moving mass passes over the cantilever pipe, the tip displacement of the pipe is influenced by the potential energy of the cantilever pipe and the deflection of the pipe; the effect is the result of the moving mass and gravity. As the velocity of fluid flow and nozzle angle increases, the natural frequency of he system is decreased at the second mode and third mode, but it is increased at the first mode. As the moving mass increases, the natural frequency of the system is decreased at all modes.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.107-113
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• 2017

Energy source of a piezo-electric harvester is vibration. Sources of vibration are machineries operated with high frequencies, constructions and people operated with low frequencies and etc. In this study, we tried to figure out power generation properties over vibrations upon angles of a piezo-cantilever for applying them to movements of the construction and/or people, which are vibration sources at low frequencies. A uni-morph cantilever with a $59mm{\times}29mm{\times}0.2mm$ piezo-electric element attached on a $71mm{\times}46mm{\times}0.25mm$ copperplate was used. A spring was attached to the lower side of the cantilever and a mass was attached on the opposite side. Also, a structure with a specific angle which is an angle in between the ground and the cantilever was prepared and then, connected to a spring or the cantilever. Then, this structure was divided into the A-type and B-type and excited in the direction of z- axis. After that, the angle between the ground and the cantilever was changed and excited by 1 to 10 Hz upon the existence of a spring and/or a mass to compare power generation properties.

• Structural Engineering and Mechanics
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• v.28 no.1
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• pp.53-67
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• 2008

Anisotropic materials are increasingly required in modern technological applications. Certainly, civil, mechanical and naval engineers frequently deal with the situation of analyzing the dynamical behaviour of structural elements being composed of such materials. For example, panels of anisotropic materials must sometimes support electromechanical engines, and besides, holes are performed in them for operational reasons e.g., conduits, ducts or electrical connections. This study is concerned with the natural frequencies and normal modes of vibration of rectangular anisotropic plates supported by different combinations of the classical boundary conditions: clamped, simply - supported and free, and with additional complexities such holes of free boundaries and attached concentrated masses. A variational approach (the well known Ritz method) is used, where the displacement amplitude is approximated by a set of beam functions in each coordinate direction corresponding to the sides of the rectangular plate. Consequently each coordinate function satisfies the essential boundary conditions at the outer edge of the plate. The influence of the position and magnitude of both hole and mass, on the natural frequencies and modal shapes of vibration are studied for a generic anisotropic material. The classical Ritz method with beam functions as spatial approximation proved to be a suitable procedure to solve a problem of such analytical complexity.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.23 no.11 s.170
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• pp.1940-1951
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• 1999

In this paper, the equations of motion of a Bernoulli-Euler cantilever beam fixed on a moving cart and carrying a lumped mass concentrated at an arbitrary position along the beam is derived. The motion of the beam-mass-cart system is analyzed through unconstrained modal analysis, and a unified characteristic equation for calculating the natural frequencies of the system is obtained. The changes of natural frequencies and the corresponding mode shapes with respect to the changes in mass ratios of the system and to the concentrated position of the lumped mass are investigated with the frequency equation, which can be generally applied to this kind of systems. The exact and assumed-mode solutions including the dynamics of the base cart are obtained, and the open-loop responses of the system by arbitrarily designed forcing function are given by numerical simulations. The results match well with physical phenomena even at the extreme cases where the concentrated mass is attached to the bottom and to the top of the beam.