• 대한기계학회논문집A
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• 제23권11호
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• pp.1904-1911
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• 1999

The most effective material in the shape memory alloy(SMA) is the TiNi alloy, because its shape recovery characteristics are very excellent. We molded the composite material with shape memory function. The fiber of it is $Ti_{50}-Ni_{50}$ shape memory alloy and matrix of it is epoxy resin(Araldite B41, Hardner HT903. Ciba Geigy), its adhesive and optical sensitivity are very excellent. It was assured that the composite material could be used as model material of photoelastic experiment for intelligent materials or structures. In this research, the composite material with shape memory function is used as model material of photoelastic experiment. Photoelastic experimental hybrid method is developed in this research, it is assured that it is useful on the obtaining stress intensity factor and the separation of stress components from only isochromatic data. The measuring method of stress intensity factor of intelligent material by photoelastic experiment is introduced. In the mode I state, we can know that stress intensity factors are decreased more than 50% of stress intensity factor of room temperature when temperature of fiber is greater than 4$0^{\circ}C$, prestrain greater than 5% and fiber volume ratio greater than 0.42% and that stress intensity factors are decreased by 100% when fiber volume ratio is greater than 0.84%, prestrain greater than 5% and temperature greater than 60 $^{\circ}C$.

• 대한기계학회논문집A
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• 제25권4호
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• pp.582-591
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• 2001

It is known that the reduced integration, modified shape function, anisoparametric and non-conforming element can reduce the error induced by stiffness locking phenomenon in the finite element analysis. In this study, we propose new anisoparametric curved beam element. The new element based on reduced minimization theory is composed of different shape functions in each displacement field. By the substitution of this modified shape function, the unmatched coefficient that cause stiffness locking in the constraint energy is eliminated. To confirm the availability of this new model, we performed numerical tests for a simple model. As a result of numerical test, the undulate stress patterns are disappeared in static analysis, and displacements and stresses are close to exact solution. Not only in the static analysis but also in the eigen analysis of free vibrated curved beam model, this element shows successful convergent results.

• 한국전산구조공학회논문집
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• 제15권1호
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• pp.127-136
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• 2002

본 논문은 교량 구조물의 손상위치 및 손상정도를 평가하기 위해 제한된 모드형상을 사용한 손상지수 방법에 기초한 실용적이며 개선된 손상평가 알고리즘을 제안한다. 손상평가 알고리즘에서 손상전 ·후의 구조물로부터 획득한 모드 벡터의 민감도 비에 근거한 손상지수를 사용하여 손상위치의 파악 및 손상정도를 평가한다. 그러나 모드형상의 진폭이 거의 영의 값을 가지는 요소에 손상이 존재하면 모드벡터 민감도 비는 무한대의 값을 가지게 되며, 이는 손상평가를 불가능하게 한다. 따라서 본 논문에서는 구조물의 모드형상과 비례하는 민감도 필터를 도입한 개선된 기법을 적용함으로써, 이러한 문제점을 극복하였으며 또한 기존의 방법보다 손상위치와 손상정도 평가에 있어 상당한 정확도의 향상을 구현하였다. 제안된 알고리즘을 검증하기 위해 단순보와 2경간 연속보에 대해 손상평가를 수행하였으며, 기존의 방법에 의한 결과와 비교하였다.

• Structural Engineering and Mechanics
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• 제52권1호
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• pp.115-136
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• 2014

In this study, an extended Kantorovich method, employing multi-term displacement functions, is applied to analyze the vibration problem of symmetrically laminated plates with arbitrary boundary conditions. The vibration behaviors of laminated plates are determined based on the variational principle of total energy minimization and the iterative Kantorovich method. The out-of-plane displacement is represented in the form of a series of a sum of products of functions in x and y directions. With a known function in the x or y directions, the formulation for the variation of total potential energy is transformed to a set of governing equations and a set of boundary conditions. The equations and boundary conditions are then numerically solved for the natural frequency and vibration mode shape. The solutions are verified with available solutions from the literature and solutions from the Ritz and finite element analysis. In most cases, the natural frequencies compare very well with the reference solutions. The vibration mode shapes are also very well modeled using the multi-term assumed displacement function in the terms of a power series. With the method used in this study, it is possible to solve the angle-ply plate problem, where the Kantorovich method with single-term displacement function is ineffective.

• 한국생산제조학회지
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• 제9권3호
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• pp.55-61
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• 2000

In this paper we have discussed on the characteristics and modeling of machined geometry which was established for the case of round shape machining also the effects of externally machined profile are analyzed and its modeling realia-bility was verified by the experiments of roundness testing especially in lathe operation. In this study we established a harmonic geometric model with the parameter harmonic function. In general we can calculate the theoretical roundness profile with an arbitrary multilobe parameter. But in real experiments only 2-5 lobe profile was frequently measured, The most frequently measured ones are 3 and 5 lobe profile in experiments. With these results we can predict that these results may be applied to round shape machining such as turning drilling boring ball screw and cylindrical grinding operation in bearing and shaft making operation with the same method. in this study simulation and experimental work were performed to show the profile behaviors. we can apply these new modeling methods in real process for the predic-tion of part profile behaviors machined such as in round shape machining operation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.659-664
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• 2000

In this paper, We have discussed on the modeling of machined outer geometry which was established for the case of round shape machining, also the effects of externally machined profile are analyzed and its modeling realiability was verified by the experiments of roundness testing, especially in lathe operation. In this study, we established harmonic geometric model with the parameter harmonic function. In general, we can calculate the theoretical roundness profile with arbitrary multilobe parameter. But in real experiments, only 2-5 lobe profile was frequently measured. the most frequently ones are 3 and 5 lobe profile in experiments. With this results, we can predict that these results may be applies to round shape machining such as turning, drilling, boring, ball screw and cylindrical grinding operation in bearing and shaft making operation with the same method. In this study, simulation and experimental work were performed to show the profile behaviors. we can apply these new modeling method in real process for the prediction of part profile behaviors machined such as in round shape machining operation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.181-186
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• 1998

A modelling method for the vibration analysis of rotating cantilever plates with a concentrated mass is presented. The equations of motion for the rotating plates with a concentrated mass located in an arbitrary position are derived. For the modelling of the concentrated mass, a mass density Dirac delta function is used. The effects of concentrated mass and its location, angular speed, and hub radius of the rotating plate on the natural frequencies are studied. Particularly, mode shape variations due to some parameter variations are investigated.

• Applied Science and Convergence Technology
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• 제24권6호
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• pp.237-241
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• 2015

The reactor impedance is calculated for a planar-type cylindrical inductively coupled plasma source by expanding the electromagnetic fields into their Fourier-Bessel series forms including the three-dimensional shape of the antenna. The mode excitation method is utilized to determine the electromagnetic fields based on a Poynting theorem-like relationship. From the obtained electromagnetic fields, a tractable form of the reactor impedance is obtained as a function of various plasma and geometrical parameters and applied to carry out a parametric study.

• 대한전기학회논문지
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• 제43권4호
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• pp.666-672
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• 1994

An H-Plane waveguide component with arbitrary shape is analyzed using finite element method(FEM) Cooperated with boundary element method(BEM). For the application of BEM in the waveguide structure, a ray representation of the waveguide Green's function is used. This technique is applied to the analysis of the waveguide inductive junction. The results are compared with the results of the mode matching technique. The comparison shows good agreement.

• 소음진동
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• 제10권2호
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• pp.353-360
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• 2000

Numerical methods are developed for calculating the natural frequencies and mode shapes of the tapered cantilever arches with variable curvature. The differential equations governing the free vibrations of such arches are derived and solved numerically, in which the effect of rotatory inertia is included. The parabolic shape is chosen as the arch with variable curvature while both the prime and quadratic arched members are considered as the tapered arch with variable curvature while both the prime and quadratic arched members are considered as the tapered arch. Comparisons the natural jfrequencies between this study and finite element method SAP 90 seve to validate the numerical method developed herein. The lowest four natural frequencies are reported as a function of four non-dimensional system parameters. The effects of both the rotatory inertia and cross-sectional shape are reported. Also, the typical mode shapes of stress resultants as well as the displacements are reported.