• Steel and Composite Structures
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• v.31 no.2
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• pp.149-158
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• 2019

The force-deformation behavior, strain distribution and failure modes of a variable damping self-centering brace (VD-SCB) are theoretically analyzed, experimentally studied, and numerically simulated to guide its design. The working principle of the brace is explained by describing the working stages and the key feature points of the hysteretic curve. A large-scale brace specimen was tested under different sinusoidal excitations to analyze the recentering capability and energy dissipation. Results demonstrate that the VD-SCB exhibits a full quasi-flag-shaped hysteretic response, high ultimate bearing capacity, low activation force and residual deformation, and excellent recentering and energy dissipation capabilities. Calculation equations of the strain distribution in different parts of the brace are proposed and are compared with the experimental data and simulated results. The developments of two failure modes are compared. Under normal circumstances, the brace fails due to the yielding of the spring blocking plates, which are easily replaced to restore the normal operating conditions of the brace. A brief description of the design procedure of the brace is proposed for application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.392-398
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• 1998

In order to check the validity of nonlinear normal modes of continuous, systems by means of the energy-based formulation, we consider a beam with a nonlinear boundary condition. The initial and boundary e c6nsl of a linear partial differential equation and a nonlinear boundary condition is reduced to a linear boundary value problem consisting of an 8th order ordinary differential equations and linear boundary conditions. After obtaining the asymptotic solution corresponding to each normal mode, we compare this with numerical results by the finite element method.

• The Journal of the Acoustical Society of Korea
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• v.15 no.2E
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• pp.63-75
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• 1996

The squeal vibration of a drum is the major source of brake noise. In this system the binary flutter model of squeal vibration was employed for the drum brake of a passenger car. The vibration analysis of a drum brake was performed by using normal modes, which are obtained by variational method. An improved method for the estimation of shoe modes is proposed and the results are compared with the exact solutions. Numerical results for the coupled system of drum and shoes good agreement with the results of experimental model analysis and those obtained by FE analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.137-140
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• 2005

This paper focuses on the premature failure of RC beams bonded with FRP. A number of failure modes for RC beams bonded with FRP have been observed in numerous experimental studies during past decade. Particularly, Rip-off failure and Debonding failure were majority failure modes in RC beams bonded with FRP. Rip-off failure occurred at the plate end due to high interfacial shear and normal stresses however Debonding failure was caused by the yielding of reinforcing bar and the increasing of shear deformation in shear span. On the basis of premature failure mechanism in RC beams bonded with FRP, Basic strengthening length and Premature failure criteria were derived

• Bulletin of the Society of Naval Architects of Korea
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• v.19 no.2
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• pp.27-31
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• 1982

The practical utilization of the frequency and normal mode equations of uniform Timoshenko beams such as those presented by Huang is not simple due to their highly trancendental nature. In this note largely simplified equations obtained for the fixed-fixed and the free-free boundary conditions, the modes of which are separable into symmetric modes and antisymmetric ones, are given. Numerical results obtains for six common-type boundary conditions show that the quantitative measure of the effect of rotary inertia and shear deformation on the natural frequency is greatly dependent upon the boundary conditions as well as the order number.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.8
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• pp.736-741
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• 2012

Squeak noise is studied by using the pin-on-disk system with aluminum pin and steel disk. Noise induced by friction is measured with respect to the normal loads and sliding speeds. The negative slope of friction-velocity curve is seen when the squeak noise occurs. It is found that the normal load influences on the sound level of squeak noise. From the hammering test, the major frequency of the squeak noise is shown to correspond to one of system modes, which implies that squeak phenomenon arises from the unstable system modes. The result of FE analysis shows that the major squeak mode is the bending mode of the pin.

• Journal of Mechanical Science and Technology
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• v.15 no.10
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• pp.1386-1397
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• 2001

In this paper, the plane elasticity equations are used to investigate the in-plane normal (mode I) and shear (mode II) behavior of a crack perpendicular to and terminating at the interface in bonded media with a graded interfacial zone. The interfacial Bone is treated as a nonhomogeneous interlayer with the continuously varying elastic modulus between the two dissimilar, homogeneous semi-infinite constituents. For each of the individual loading modes, based on the Fourier integral transform technique, a singular integral equation with a Cauchy kernel is derived in a separate but parallel manner. In the numerical results, the values of corresponding modes of stress intensity factors are illustrated for various combinations of material and geometric parameters of the bonded media in conjunction with the effect of the material nonhomogeneity within the graded interfacial zone.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.2
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• pp.127-136
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• 1996

Dynamic analysis of a three-axle heavy truck is carried out with rigid body model and flexible body model. To see the effects of chassis flexibility, the chassis is modeled as flexible body. The mass matrix, stiffness matrix, and vibration normal modes of the chassis are obtained by a finite element analysis program, and four vibration normal modes are used in the flexible body model. The vehicle model consisting of a frame, a cab, suspensions, an engine, a deck, a seat, and tires, has total 77 degrees of freedom. The result shows that the peaked acceleration in the flexible model is lower than that of the rigid body model.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.199-202
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• 2009

Scan design is currently the most widely used structured Design For Testability approach. In scan design, all storage elements are replaced with scan cells, which are then configured as one or more shift registers(also called scan chains) during the shift operation. As a result, all inputs to the combinational logic, including those driven by scan cells, can be controlled and all outputs from the combinational logic, including those driving scan cells, can be observed. The scan inserted design, called scan design, is operated in three modes: normal mode, shift mode, and capture mode. Circuit operations with associated clock cycles conducted in these three modes are referred to as normal operation, shift operation, and capture operation, respectively. In spite of these, scan design methodology has defects. They are power dissipation problem and test time during test application. We propose a new methodology about scan shift clock operation and present low power scan design and short test time.

• Applied Science and Convergence Technology
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• v.25 no.2
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• pp.42-45
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• 2016

A two-dimensional metal hole array (2DMHA) structure is fabricated by conventional photo-lithography and electron beam evaporation. The transmittance of the 2DMHA is measured at long wave infrared (LWIR) wavelengths (${\lambda}{\sim}10$ to $24{\mu}m$). The 2DMHA sample shows transmittance of 70 and 67% at $15.4{\mu}m$ due to plasmonic resonance with perforated silver and gold thin films, respectively, under surface normal illumination at LWIR wavelengths. The measured infrared spectrum is separated into two peaks when the size of the hole becomes larger than a half-pitch of the hole array. Six degenerated plasmon modes (1,0) at the metal/Si surface split to three modes at an incident beam angle of $45^{\circ}$ with respect to the surface normal direction, and wavelength shifts of the transmitted spectrum are observed in a red shift and blue shift at the same time.