• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.149-153
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• 2003

The most important thing in measuring the tool wear is to set up the measurement base. The end mill that is being used for machining is difficult to set up the base and to measure the tool wear because of geometric properties of that such as a helix and relief angle. In this study, a new instrument using spindle orientation function in end milling is developed to measure tool wear and evaluated by measuring system on the machine. Finally, this new method makes possible the wear measurement of same position and reduces measuring time compared with measuring methods such as the microscope and CCD.

• Proceeding of KASS Symposium
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• 2005.05a
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• pp.147-153
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• 2005

The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is originazed by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

• Journal of KSNVE
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• v.9 no.6
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• pp.1193-1199
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• 1999

This paper deals with the free vibrations of circular curved beams with thin-walled cross-section. The differential equation for the coupled flexural-torsional vibrations of such beams with warping is solved numerically to obtain natural frequencies and mode shapes. The Runge-Kutta and determinant search methods, respectively, are used to solve the governing differential equation and to compute the eigenvalues. The lowest three natural frequencies and corresponding mode shapes are calculated for the thin-walled horizontally curved beams with hinged-hinged, hinged-clamped, and clamped-clamped end constraints. A wide range of opening angle of beam, warping parameter, and two different values of slenderness ratios are considered. Numerical results are compared with existing exact and numerical solutions by other methods.

• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.475-502
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• 2016

Nanobeams are widely used as a structural element for nanodevices and nanomachines. The development of nano-sized machines depends on proper understanding of mechanical behavior of these nano-sized beam elements. Small length scales such as lattice spacing between atoms, surface properties, grain size etc. are need to be considered when applying any classical continuum model. In this study, Eringen's nonlocal elasticity theory is incorporated into classical beam model considering the effects of axial extension and the shear deformation to capture unique static behavior of the nanobeams under continuum mechanics theory. The governing differential equations are obtained for curved beams and solved exactly by using the initial value method. Circular uniform beam with concentrated loads are considered. The displacements, slopes and the stress resultants are obtained analytically. A detailed parametric study is conducted to examine the effect of the nonlocal parameter, mechanical loadings, opening angle, boundary conditions, and slenderness ratio on the static behavior of the nanobeam.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.105-110
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• 2007

The differential equations governing free, in-plane vibrations of circular curved beams with elastic springs at beth ends, including the effects of axial deformation, rotatory inertia and shear defamation. are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies are calculated over a wide range of non-dimensional system parameters, the radial, tangential and rotational spring parameters, the subtended angle, the slenderness ratio and the shear parameter.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.9-18
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• 1996

The primary objective of this paper is to grasp many characteristics of buckling behavior of latticed spherical domes under various conditions. The Arc-Length Method proposed by E.Riks is used for the computation and evaluation of geometrically nonlinear fundamental equilibrium paths and bifurcation points. And the direction of the path after the bifurcation point is decided by means of Hosono's concept. Three different nonlinear stiffness matrices of the Slope-Deflection Method are derived for the system with rigid nodes and results of the numerical analysis are examined in regard in geometrical parameters such as slenderness ratio, half-open angle, boundary conditions, and various loading types. But in case of analytical model 2 (rigid node), the post-buckling path could not be surveyed because of Newton-Raphson iteration process being diversed on the critical point since many eigenvalues become zero simultaneously.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.151-156
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• 1996

The differential equations governing free, out of plane vibrations of horizontally curved beams are derived and solved numerically to obtain the natural frequencies and the mode shapes. The Runge-Kutta method and Regula-Falsi method are used to integrate the differential equations and to determine the natural frequencies, respectively. In nu- merical examples, the hinged-clamped end constraint is considered and four lowest frequency parameters are reported as functions of four non-dimensional system parameters: (1) opening angle, (2) slenderness ratio, (3) shear parameter and (4) stiffness parameter. Also, typical mode shapes of displacements and stress resultants are shown.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1254-1259
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• 2001

This paper deals with the free vibrations of circular arches with variable cross-section. The differential equations governing free, in-plane vibrations of tapered circular arches, including the effects of rotatory inertia, shear deformation and axial deformation, are derived and solved numerically to obtain frequencies and mode shapes. Numerical results are calculated for the quadratic arches with hinged-hinged and clamped-clamped end constraints. Three general taper types for a rectangular section are considered. The lowest four natural frequencies and mode shapes are presented over a range of non-dimensional system parameters： the subtended angle, the slenderness ratio and the section ratio.

• Advances in nano research
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• v.7 no.6
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• pp.391-403
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• 2019

In this article the frequency response analysis of curved magneto-electro-viscoelastic functionally graded (CMEV-FG) nanobeams resting on viscoelastic foundation has been carried out. To this end, the study incorporates the Euler-Bernoulli beam model in association with Eringen's nonlocal theory to incorporate the size effects. The viscoelastic foundation in the current investigation is assumed to be the combination of Winkler-Pasternak layer and viscous layer of infinite parallel dashpots. The equations of motion are derived with the aid of Hamilton's principle and the solution to vibration problem of CMEV-FG nanobeams are obtained analytically. The material gradation is considered to follow Power-law rule. This study thoroughly investigates the influence of prominent parameters such as linear, shear and viscous layers of foundation, structural damping coefficient, opening angle, magneto-electrical field, nonlocal parameter, power-law exponent and slenderness ratio on the frequencies of FG nanobeams.

• Advances in nano research
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• v.7 no.3
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• pp.145-155
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• 2019

In this article, the influence of small scale effects on the free vibration response of curved magneto-electro-elastic functionally graded (MEE-FG) nanobeams has been investigated considering nonlocal elasticity theory. Power-law is used to judge the through thickness material property distribution of MEE nanobeams. The Euler-Bernoulli beam model has been adopted and through Hamilton's principle the Nonlocal governing equations of curved MEE-FG nanobeam are obtained. The analytical solutions are obtained and validated with the results reported in the literature. Several parametric studies are performed to assess the influence of nonlocal parameter, magnetic potential, electric voltage, opening angle, material composition and slenderness ratio on the dynamic behaviour of MEE curved nanobeams. It is believed that the results presented in this article may serve as benchmark results in accurate analysis and design of smart nanostructures.