• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.1
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• pp.9-17
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• 2011

In this paper, the general equation of motion of damped sandwich beam with multi-viscoelastic material layer was derived based on the equation presented by Mead and Markus. The viscoelastic layer, which has characteristics of complex shear modulus, was assumed to be dominantly under shear deformation. The equation of motion of n-layered damped sandwich beam in bending could be represented by (n+3)th order ordinary differential equation. Finite element model for the n-layered damped sandwich beam was formulated and programmed using higher order shape functions. Several numerical examples were implemented to show the effects of damped material.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.18-21
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• 2000

A nonconstact technique for reducing the core loss of a grain oriented silicon steel has been developed by the use of mechanical scribing Q-switched laser plasma jet or electron beam irradiation. Among these methods electron beam irradiation has advantages of domain refining without any deformation or damage of insulating film on the surface of a grain criented Si-Fe. Over the past years this processing was performed in vaccum of 10-4 Torr or below causing the problem of high cost and difficulty of continuous works. In this paper a miniature electron permeable window through which electron beam energy 4-80keV and average current 0.1-2mA. were obtained for electron beam irradiating on air was designed and manufactured.

• Steel and Composite Structures
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• v.9 no.1
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• pp.19-38
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• 2009

The present paper provides test data to evaluate the seismic performance of recycled aggregate concrete (RAC) filled steel square hollow section (SHS) beam-columns. Fifteen specimens, including 12 RAC filled steel tubular (RACFST) columns and 3 reference conventional concrete filled steel tubular (CFST) columns, were tested under reversed cyclic flexural loading while subjected to constant axially compressive load. The test parameters include: (1) axial load level (n), from 0.05 to 0.47; and (2) recycled coarse aggregate replacement ratio (r), from 0 to 50%. It was found that, generally, the seismic performance of RACFST columns was similar to that of the reference conventional CFST columns, and RACFST columns exhibited high levels of bearing capacity and ductility. Comparisons are made with predicted RACFST beam-column bearing capacities and flexural stiffness using current design codes. A theoretical model for conventional CFST beam-columns is employed in this paper for square RACFST beam-columns. The predicted load versus deformation hysteretic curves are found to exhibit satisfactory agreement with test results.

• Structural Engineering and Mechanics
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• v.2 no.2
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• pp.141-156
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• 1994

In this paper, the effect of material elasticity was evaluated through a simple model as proposed by Wang and Yu (1991), for yield mechanisms of a cantilever beam under tip pulse loading. The beam was assumed rigid-perfectly plastic but instead of the usual fully clamped constraints at its root, an elastic-perfectly plastic rotational spring was introduced there so the system had a certain capacity to absorb elastic energy. Compared with a rigid-perfectly plastic beam without a spring root, the present beam-spring model showed differences in the initial plastic hinge position and the minimum magnitude of the dynamic force needed to produce a plastic failure. It was also shown that various failure responses may happen while the hinge travels along the beam segment towards the root, rather than a unique response mode as in a rigid perfectly plastic analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.121-126
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• 2000

The attaching method of different types of structure and explanation of stress transfer mechanism are at important issue as beam having definitive factor such as the anchorage of RC main bar, the stress transfer of anchorage-end S member, RC member-anchorage, anchorage-end S member in the composite beam of S and RC member. In this study, the structural properties of composite beam according to attaching method of main bar about end RC-middle S beam were investigated in order to use them as fundamental data for the development of composite structure member. Throughout a series of study, it was shown that the proof stress of main bar - flange welding specimen is the highest and there is no difference between the deformation-properties according to attaching method of main bar.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2011-2018
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• 2003

To analyze the bending collapse behavior of an aluminum square tube beam under a bending load, a finite element simulation for the four-point bending test has been performed. Using an aluminum tube beam specimen partly inserted with two steel bars, the local buckling deformation near the center of the tube beam was induced. The maximum bending load and the bending collapse behavior obtained from the numerical simulation were in good agreement with experimental results. Using a combination of the four-point bending test and its finite element simulation, analysis of the local buckling and the accompanied bending collapse behavior of aluminum tube beam could be quantitative accomplished.

• Coupled systems mechanics
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• v.8 no.6
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• pp.537-553
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• 2019

In this paper we present geometrically exact Kirchhoff's initially curved planar beam model. The theoretical formulation of the proposed model is based upon Reissner's geometrically exact beam formulation presented in classical works as a starting point, but with imposed Kirchhoff's constraint in the rotated strain measure. Such constraint imposes that shear deformation becomes negligible, and as a result, curvature depends on the second derivative of displacements. The constitutive law is plasticity with linear hardening, defined separately for axial and bending response. We construct discrete approximation by using Hermite's polynomials, for both position vector and displacements, and present the finite element arrays and details of numerical implementation. Several numerical examples are presented in order to illustrate an excellent performance of the proposed beam model.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.2
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• pp.25-29
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• 2006

Analysis of structures which are composed of numerous repeated unit structures can be simplified by using homogenized properties. If the unit structure is repeated in one direction, the whole structure may be regarded as a beam. Once the effective stiffness is obtained from the analysis of the unit structure in a proper way, the effort for the detail modeling of the global structure is not required, and the real structure can be replaced simply with a beam. This study proposes a kinematical periodicity constraint to be imposed on the FE model of the unit structure, which improves the accuracy of the effective stiffness. The method is employed to a one dimensionally arrayed 3D structure containing periodically repeated unsymmetrical holes. It is demonstrated that the deformation behavior of the homogenized beam agrees well with that of the real structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.1
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• pp.68-78
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• 1996

A study of the natural vibraion of Timoshenko beam with a laminar tear is presented. An analytic model, based on the transverse and longitudinal vibration of beams is employed to determine the natural frequencies. A specific example are given to show the effects of rotary inertia, and shear deformation on the natural frequencies of the beam with a laminar tear. the variations of matural frequencies of beam with the changes of size and location of laminar tear are plotted for several thickness ratio.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.8
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• pp.742-751
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• 2013

The vibration analysis of a rotating cantilever beam made-up of functionally graded materials is presented based on Timoshenko beam theory. The material properties of the beams are assumed to be varied through the thickness direction following a simple power-law form. The frequency equations, which are coupled through gyroscopic coupling terms, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of power-law exponent, angular speed, length to height ratio and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their results.