• 대한기계학회논문집A
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• 제20권12호
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• pp.3792-3803
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• 1996

Since the skew beam element has two curvatures which are a curvature and a torsion, spatial behavior of curved beam which cannot be included in one plane can be anlayzed by emploting the skew beam element. The $C^{0}$-continuous skew beam element shows the stiffness locking phenomenon when full integration is employed. The locking phenomenpn is characterized by two typical phenomena ; one is the much smaller displacement thant the exact one and theother is the undelation phenomenon is stress distribution. In this paper, we examine how unmatched coefficient in the constrained energy brings about the locking by Reduced Minimization theory. We perform the numerical ones. These comparisons show that uniformly full integration(UFI), which employs full integration for the constrained energy, entails the locking phenomenon. But the use of uniformly reduced integration(URI) of selectively reduced integration(SRI), which employs reduced integration for constrained energy, does not produce the significant errors of displacements of the undulation phenomenon in stress distribution since they do not entails the locking, Additionally, the error due to the approximated parameters for describing the geometry of skew beam is examined.d.

• 한국자동차공학회논문집
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• 제5권3호
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• pp.220-228
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• 1997

We discuss finite element approximation and use a Mindlin plate element based upon uniformly reduced numerical integration. The finite element selected for use in this work is a four-node, bilinear displacement element based upon the Mindlin theory of plates. Such elements show good accuracy for laminated composite plates when reduced numerical integration is used to evaluate the element marices. This study presents both the experimental and F.E. results for the natural frequencies of CFRPURETHANE-CFRP Composite plate. Good agreement between experimental and calculated frequencies is achived.

• 대한수학회지
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• 제33권2호
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• pp.235-247
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• 1996

Many numerical computations in science and engineering can only be solved approximately since the available infomation is partial. For instance, for problems defined ona space of functions, information about f is typically provided by few function values, $N(f) = [f(x_1), f(x_2), \ldots, f(x_n)]$. Knwing N(f), the solution is approximated by a numerical method. The error between the true and the approximate solutions can be reduced by acquiring more information. However, this increases the cost. Hence there is a trade-off between the error and the cost.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.333-340
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• 2004

This paper deals with geometric nonlinear analyses using a new meshfree technique which improves the numerical integration accuracy. The new method called the Petrov-Galerkin natural element method (PGNEM) is based on the Voronoi diagram and the Delaunay triangulation which is based on the same concept used for conventional natural element method called the Bubnov-Galerkin natural element method (BGNEM). But, unlike BGNEM, the test shape function is differently chosen from the trial shape function. In the linear static analysis, it is ensured that the numerical integration error of the PGNEM is remarkably reduced. In this paper, the PGNEM is applied to large deformation problems, and the accuracy of the proposed numerical technique is verified through the several examples.

• 대한기계학회논문집
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• 제5권3호
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• pp.217-222
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• 1981

The stress analysis of two-orthotropic layer, adhesively bonded structures is considered. An orthotropic plate has a through-crack of finite length and is adhesively bounded by a sound orthotropic plate. The problem is resuced to a pair of Fredholm integral equations ofthe second kind. Using a numerical integration scheme to evaluate the intgrals, The integral equations are reduced to a system of algebraic equations. By solving these equations some numerical results for stress intensity factors are presented for various crack lengths.

• 대한수학회지
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• 제49권1호
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• pp.99-112
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• 2012

This paper attempts to present a numerical method for solving optimal control problems. The method is based upon constructing the n-th degree Jacobi polynomials to approximate the control vector and use differentiation matrix to approximate derivative term in the state system. The system dynamics are then converted into system of algebraic equations and hence the optimal control problem is reduced to constrained optimization problem. Numerical examples illustrate the robustness, accuracy and efficiency of the proposed method.

• Structural Engineering and Mechanics
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• 제45권6호
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• pp.853-865
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• 2013

Inflatable panels made of modern and new textile materials can be inflated at high pressure to have a high mechanical strength. This paper is based on the finite element method as a general solution to determine the characteristics of deformed inflatable panels at high pressure in various end and loading conditions. Proposed method is based on the construction of weak form of formulation and application of Reduced Integration Element method (RIE) to solve the numerical problem of shear locking. The numerical results are validated as an outcome of comparison with other published results.

• 한국정밀공학회지
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• 제25권9호
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• pp.95-102
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• 2008

A miniature metal bellows is used to minimize the excessive flow of the cryogenic gas in Joule-Thomson micro cryocooler. It is made of metal alloy and its geometry is axisymmetric. The bellows is filled with high pressure gas. It contracts or expands in the axial direction for a wide change of temperature, because the pressure and volume inside the bellows must be satisfied with state equation of the gas. Therefore, in order to design the bellows in Joule-Thomson micro-cryocooler, it is important to evaluate deformation of the bellows under internal pressure exactly. Considering geometric nonlinearity, deformations analysis of the bellows were obtained by a commercial finite element code ANSYS, The bellows was modeled by 3-node axisymmetric shell elements with reduced integration. Experiments were also performed to prove the validity of proposed numerical analysis. The results by numerical analysis and experiments were shown in good agreements.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1274-1279
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• 2003

In this paper, a new meshfree technique which improves the numerical integration accuracy is introduced. This new method called the Petrov-Galerkin natural element(PG-NE) is based on the Voronoi diagram and the Delaunay triangulation which is based on the same concept used for conventional natural element method called the Bubnov-Galerkin natural element(BG-NE). But, unlike BG-NE method, the test shape function is differently chosen from the trial shape function. The proposed technique ensures that the numerical integration error is remarkably reduced.

• Coupled systems mechanics
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• 제1권3호
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• pp.235-245
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• 2012

The nonlinear resonant response of an axially moving beam is investigated in this paper via two different numerical techniques: the pseudo-arclength continuation technique and direct time integration. In particular, the response is examined for the system in the neighborhood of a three-to-one internal resonance between the first two modes as well as for the case where it is not. The equation of motion is reduced into a set of nonlinear ordinary differential equation via the Galerkin technique. This set is solved using the pseudo-arclength continuation technique and the results are confirmed through use of direct time integration. Vibration characteristics of the system are presented in the form of frequency-response curves, time histories, phase-plane diagrams, and fast Fourier transforms (FFTs).