• Structural Engineering and Mechanics
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• v.35 no.4
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• pp.387-407
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• 2010

In this paper, using perturbation and Galerkin method, the response of a resonant viscoelastic microbeam to an electric actuation is obtained. The microbeam is under axial load and electrical load. It is assumed that midplane is stretched, when the beam is deflected. The equation of motion is derived using the Newton's second law. The viscoelastic model is taken to be the Kelvin-Voigt model. In the first section, the static deflection is obtained using the Galerkin method. Exact linear symmetric mode shape of a straight beam and its deflection function under constant transverse load are used as admissible functions. So, an analytical expression that describes the static deflection at all points is obtained. Comparing the result with previous research show that using deflection function as admissible function decreases the computation errors and previous calculations volume. In the second section, the response of a microbeam resonator system under primary and secondary resonance excitation has been obtained by analytical multiple scale perturbation method combined with the Galerkin method. It is shown, that a small amount of viscoelastic damping has an important effect and causes to decrease the maximum amplitude of response, and to shift the resonance frequency. Also, it shown, that an increase of the DC voltage, ratio of the air gap to the microbeam thickness, tensile axial load, would increase the effect of viscoelastic damping, and an increase of the compressive axial load would decrease the effect of viscoelastic damping.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.61-71
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• 2004

The performance evaluation and deflection of 3 spans concrete simplicity slab bridge analyzed by non-destructive and loading test. Compressive strength of slab and pier appeared in the range of each 353∼366 kgf/$cm^2$ and 152∼215 kgf/$cm^2$ in rebound number test. Also, it appeared that concrete quality of slab was good after performance improvement. The average compressive strength of slab by core picking appeared 229 kg/$cm^2$. In reinforcing bar arrangement test of span and member, it appeared that horizontal and vertical reinforcing bar was arranged to fixed interval. The value of calculation deflection that carried structural analysis with deflection analysis wave in static loading test appeared higher than that of experimental deflection and it appeared that hardness of this bridge was good. Maximum impact factor that estimated from deflection by running speed in dynamic loading test appeared by 0.216 in 10 km/hr running speed.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.188-193
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• 1998

This paper describes static and dynamic weak point analysis of spindle systems to eliminate high concentrated bending point on spindle and improve total stiffness of spindle systems. The weak point analysis is based on the evaluation of bending curves of spindles. For static weak point analysis the bending curve is derived from static deflection curve and for dynamic weak point analysis it is derived from the mode shape curves in consideration of the transfer function at exciting point. The validity of the weak point search methodology is verified by comparison of the static deflection, the natural frequency and the dynamic compliance between the original and the improved spindle.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2311-2318
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• 2005

Progress in the LCD industries has been very rapid. Therefore, their manufacturing lines require larger LCD glass-handling robots and more precise path control of the robots. In this paper, we present two practical advanced algorithms for high-precision path generation of an LCD glass-handling robot. One is high-precision path interpolation for continuous motion, which connects several single motions and is a reliable solution for a short robot cycle time. We demonstrate that the proposed algorithm can reduce path error by approximately 91% compared with existing algorithms without increasing cycle time. The second is real-time static deflection compensation, which can optimally compensate the static deflection of the handling robot without any additional sensors, measurement instruments or mechanical axes. This reduces vertical path error to approximately 60% of the existing system error. All of these algorithms have been commercialized and applied to a seventh-generation LCD glass-handling robot.

• Advances in Computational Design
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• v.7 no.2
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• pp.99-112
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• 2022

This research has been devoted to examine nonlinear static bending analysis of smart beams with nano dimension exposed to thermal environment. The beam elastic properties are corresponding to piezo-magnetic material of different compositions. The large deflection analysis of the beam has been performed assuming that the beam is exposed to transverse uniform pressure. Based on the rule of Hamilton, the governing equations have been derived for a nonlocal thin beam and solved using differential quadrature method. Temperature variation effect on nonlinear deflection of the smart beams has been studied. Also, the beam deflection is shown to be affected by electric voltage, magnetic intensity and material composition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.211-216
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• 2012

This paper presents methods to reduce the deflection of the battery-supporting structure on on-line electric vehicles (OLEVs). First, by testing various battery locations, a location is found that increases the dynamic stiffness of the OLEV. Second, static analysis is conducted to analyze the maximum deflection caused by the battery weight. In order to reduce the amount of deflection, the contributions of the battery-supporting structures are analyzed, and reinforcements are inserted. Then, another static analysis is conducted to compare the results of the base model and modified model. Consequently, through the static analysis, both the base model and modified model are similarly improved in terms of deflection, but the modified model is better than the base model at reducing the mass.

• Computers and Concrete
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• v.19 no.1
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• pp.1-6
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• 2017

Prestressed concrete I-girders are subject to different load types at their construction stages. At the time of strand release, i.e., detensioning, prestressed concrete girders are under the effect of dead and prestressing loads. At this stage, the camber, total net upward deflection, of prestressed girder is summation of the upward deflection due to the prestressing force and the downward deflection due to dead loads. For the calculation of the upward deflection, it is generally considered that prestressed concrete I-girder behaves linear-elastic. However, the field measurements on total net upward deflection of prestressed I-girder after detensioning show contradictory results. In this paper, camber calculations with the linear-elastic beam and elastic-stability theories are presented. One of a typical precast I-girder with 120 cm height and 31.5 m effective span length is selected as a case study. 3D finite element model (FEM) of the girder is developed by SAP2000 software, and the deflections of girder are obtained from linear and nonlinear-static analyses. Only geometric nonlinearity is taken into account. The material test and field measurement of this study are performed at prestressing girder plant. The results of the linear-elastic beam and elastic-stability theories are compared with FEM results and field measurements. It is seen that the camber predicted by elastic-stability theory gives acceptable results than the linear-elastic beam theory while strand releasing.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1669-1680
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• 1992

This paper deals with the prediction of cutting force and tool deflection and it's application in the flexible ball end milling process. Machining accuracy is determined by the static stiffness of tool system and the instantaneous cutting force. The static stiffness of tool system consists of the stiffness of holer and the stiffness of ball end mill. The stiffness of holder was obtained from the experimental result, and the stiffness of ball end mill with two flutes was theoretically analyzed by the finite elements method. In cutting process, the instantaneous cutting force is dependent upon the instantaneous feed and pick feed(radial depth of cut) which are varied by tool deflection. For the calculation of cutting force and deflection of ball end mill, iteration method is used with the linear interpolation to the data of cutting force obtained from rigid ball end mill and the data of tool deflection. In this paper, a for enhancing accuracy is discussed. And the selection of helix angle for minimizing machining error is also discussed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.31-36
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• 2006

In this study, nonlinear static aeroelastic analysis system for a high-aspect-ratio wing are developed using the transonic small disturbance (TSD) and large deflection beam theory and validated. For the coupling between fluid and structure, the transformation of displacement from the structural mesh to aerodynamic one is performed by the shape function of the beam finite element and the inverse transformation of force by work equivalent load concept. Also, for the static aeroelastic analysis of the wing the use of TSD aerodynamics are justified. The validation of the system includes one of the efficient transformation methods of force and displacement.

• Journal of applied mathematics & informatics
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• v.10 no.1_2
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• pp.217-226
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• 2002

A circular plate kept zero initial temperature is heated for a certain interval of time over a concentric circular region of the upper face. Deflection is obtained by using Laplace transform technique. Taking the plate material to be aluminium, central deflection is obtained for several values of time and the results shown graphically.