• 대한기계학회논문집A
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• 제22권1호
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• pp.215-226
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• 1998

This paper addresses an analytical approach to tolerance and reliability analysis of mechanical systems with uncertainty. Many mechanical systems consist of links and lubricated joints. The mobility method is applied to consider lubrication effects and the clearance vector model is used to stochastically define a mechanism for tolerance and reliability analysis. To show the validity of the proposed method, a four-bar path generator and a slider-crank mechanism are considered. The results obtained by applying the proposed method are compared with those by Monte-Carlo simulation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1505-1510
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• 2007

Recently, efficient manufacturing of high precision is an important issue in modern industry as more variety of industrial products is being designed with compound surfaces. Rapid CAD data generation can be possible based on a non-contact type CMM of object through the use of reverse engineering. However, some registration to match the data measured from various directions into a common coordinate system is required. Also, the error can happen if it uses the conventional method to large product of thin thickness. So it is necessary to develop a new method, which was designed for the registration of large and thin products. Additionally, an algorithm to pick up coordinates for the newly designed method was proposed.

• 한국재난정보학회 논문집
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• 제5권2호
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• pp.140-152
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• 2009

Recently the occurrence ratio of mechanical accidents in industrial disaster of korea is increased, but very little accident information has been given regarding the prevention of mechanical accidents. In this study, mechanical accidents by the analysis of industrial accident case was examined. And it was proposed the risk assessment method and building database for investigation of risk factors in mechanical accident. As a result, from mechanical accidents database, it was found that the occurrence ratio of mechanical accident by constriction and falling etc. is very high and death ratio by mechanical accident is larger than that of usual accident. And we applied the quantitative risk assessment method proposed by this study in the mechanical accident analysis of a domestic manufacturer. From the results, the risk factors due to constriction, curling, falling and scattering are principal causes of mechanical accidents. These result is similar to that of the analysis of mechanical accidents for recent 12 years in korea.

• KSTLE International Journal
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• 제3권2호
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• pp.110-113
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• 2002

The lubricative characteristics of negative pressure slider were performed by using coordinate transform method. Governing equation is derived by applying generalized coordinate system to the divergence formulation method. This method makes it possible to deal with an arbitrary configuration of a lubricated surface. The pressure profile of the slider is calculated. These results are compared to that from direct numerical method. The steady-state, including minimum film thickness, pitching and rolling angle are calculated by multi-dimensional Newton-Rapshon method. The stiffness and damping characteristics are also calculated.

• Journal of Mechanical Science and Technology
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• 제20권1호
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• pp.94-109
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• 2006

An improved meshfree method called the Petrov-Galerkin natural element (PG-NE) method is introduced in order to secure the numerical integration accuracy. As in the Bubnov-Galerkin natural element (BG-NE) method, we use Laplace interpolation function for the trial basis function and Delaunay triangles to define a regular integration background mesh. But, unlike the BG-NE method, the test basis function is differently chosen, based on the Petrov-Galerkin concept, such that its support coincides exactly with a regular integration region in background mesh. Illustrative numerical experiments verify that the present method successfully prevents the numerical accuracy deterioration stemming from the numerical integration error.

• 대한기계학회논문집A
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• 제22권1호
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• pp.64-72
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• 1998

This paper was undertaken to develop the fracture toughness testing method using small and single specimen compared to the conventional method in evaluating elastic-plastic fracture toughness of the superconducting magnet structural material at cryogenic temperature. The elastic-plastic fracture toughness test was conducted by using the unloading compliance method recommended by ASTM E813-89 to accomplish the above purpose. And, the 20% side-grooved 0.5TCT and 1TCT specimens were used to evaluate the fracture toughness by using as possible as miniaturized CT specimen. The unloading compliance method was a very useful method in evaluating elastic-plastic fracture toughness at cryogenic temperature. It could be taken valid fracture toughness values by using 20% side-grooved 0.5TCT specimen recommended by ASTM E813-89.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1615-1622
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• 2002

The purpose of this study is comparing cold expansion method with interference fit. Cold expansion method and interference fit of fastener hole is using in the aerospace industry. These treatment lead to an improvement of fatigue life to the compressive residual stresses developed on the hole surface. But Research is nothing to about difference effect of between cold expansion method and interference fit. So, this paper, it is shown that Comparing cold expansion method with interference fit using the finite element method. It is further shown that residual stress distribution according to plate thickness and clamping force.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.340-346
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• 2008

A level-set method is developed for computation of drop motions in various engineering applications. Compared with the volume-of-fluid method based on a non-smooth volume-fraction function, the LS method can calculate an interface curvature more accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries unlike the VOF method requiring much more complicated geometric calculations. The LS method is applied to simulation of inkjet process, thin film pattering and droplet collisions.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.340-346
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• 2008

A level-set method is developed for computation of drop motions in various engineering applications. Compared with the volume-of-fluid method based on a non-smooth volume-fraction function, the LS method can calculate an interface curvature more accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries unlike the VOF method requiring much more complicated geometric calculations. The LS method is applied to simulation of inkjet process, thin film pattering and droplet collisions.

• 대한기계학회논문집A
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• 제25권3호
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• pp.548-553
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• 2001

A new method to estimate the elastic-plastic J-integral and the crack tip opening displacement (COD) for circumferential through-wall cracked pipes under tension and under bending is proposed for Leak-Before-Break (LBB) analysis. Being based on the reference stress method with further modifications, the proposed method is simple to use and easy to be generalised in practice. Comparison of the CODs, predicted using the proposed method with published pipe test data show overall excellent agreement.