• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.190-196
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• 2003

The load sharing and teeth deflection of helical gear system are analyzed to investigate the deformation overlap. The deformation overlap, which is calculated by the results of displacement analysis, is suggested as the basis for the tooth profile modification. Helical gear systems are formulated as contact problems, and solved by elastic contact theory and FEM. The developed computer program, which offers gear teeth deflection and deformation overlap, will be of much help to the improved design of manual transmissions for automobiles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.5
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• pp.758-763
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• 2003

A profile shifted gear system was analyzed to select the optimum profile shift coefficient, which minimizes gear teeth deflection. Contact force and deformation overlap were calculated by means of FEM and contact theory. The deformation overlap is suggested for an effective indicator to represent the whole deformation of gear system. The optimum value of profile shift coefficients was presented with respect to the deformation of gear system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.194-199
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• 2003

In this paper, elastic deformations of several gear teeth are analyzed. The contact between a gear and pinion is modeled as a contact problem. The deformation overlap, which is defined as the interference due to deformation of gear teeth, is defined to represent the deformation characteristics of profile shifted spur sear system. The calculated deformation overlap shows teeth interference in the deformed state of a Rear system.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.208-214
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• 1999

The purpose of this paper is to develop a profile modification technique of spur gears and its computer program for the prevention of gear tooth overlap. In the gear system, tooth overlap produces an impact at the initial contact of some tooth pairs. In this analysis, contact surface was assumed to be unbonded and frictionless under small deformation and stain. The problem is formulated by a variational statement with inequality constraint. Tooth load sharing is obtained by the application of contact theory, and overlap is known by the analysis of deformation. After carrying out the profile modification of gear tooth, we verified the reasonable results.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.105-111
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• 2015

Since 2007, Insurance Institute of Highway Safety(IIHS) has conducted the new bumper test using bumper barrier to estimate the repair cost of impacted vehicle. In this study, for the front body FE model of a medium size passenger car analyzes were carried out to optimize the shape of backbeam center reinforcement bracket. First, overlap effect was examined with changing the overlap magnitude and spot welds were added along the backbeam center line for reducing the section shear deformation. Next, for an overlap model design parameter study was performed for the bracket. Thickness effect was examined and an inner reinforcement was added to the bracket. Also, the lower part of bracket was deleted and additionally the bracket length was extended. The results were discussed in terms of backbeam backward deflection, barrier backstop intrusion and weight. Compared with the current design, the final model showed 44.1% bracket weight reduction with 30.0% decrease of backbeam deflection.

• Journal of Adhesion and Interface
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• v.5 no.2
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• pp.14-26
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• 2004

For reliable determination of mechanical characteristics of adhesively bonded joints used e.g. as input data for computer-aided design of complex components, the thick-adherend tensile-shear test according to ISO 11003-2 is the most important material testing method. Although the total displacement of the joint is measured across the polymer layer directly in the overlap zone in order to minimize the influence of the stepped adherends, the substrate deformation must be taken into account within the framework of the evaluation of the shear modulus and the maximum shear strain, at least when high-strength adhesives are applied. In the standard ISO 11003-2 version of 1993, it was prescribed to perform the substrate deformation correction by means of testing a one-piece reference specimen. The authors, however, pointed to the excessive demands on the measuring accuracy of the extensometers connected with this technique in industrial practice and alternatively proposed a numerical deformation analysis of a dummy specimen. This idea of a mathematical correction was included in the revised ISO 11003-2 version of 2001 but in the simplified form of an analytical method based on Hooke's law of elasticity for small strains. In the present work, it is shown that both calculation techniques yield considerably discordant results. As experimental assessment would require high-precision distance determination (e.g. laser extensometer), finite element analyses of the deformation behavior of the bonded joint are performed in order to estimate the accuracy of the obtained substrate deformation corrections. These simulations reveal that the numerical correction technique based on the finite element deformation modeling of the reference specimen leads to considerably more realistic results.

• Tribology and Lubricants
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• v.24 no.5
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• pp.241-249
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• 2008

This paper describes the tribological effects on the nonlinear behavior of a spur gear pair with one-way clutch according to the direct contact elastic deformation model over a wide range of speeds, considering the hydrodynamic effects. The effects of various lubrication parameters, such as viscosity, film width, and friction, on the nonlinear dynamic behavior were analyzed. Forces due to the entraining velocity and the hydrodynamic friction were about two orders smaller than normal forces over the whole speed range. While the viscosity has a strong effect on the behavior of gear pair systems, friction has very little effect on torsional behavior. The inclusion of the hydrodynamic effect facilitates nonlinearity by increasing the overlap and damping, as well as decreasing elastic deformation and tooth reaction forces.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.73-80
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• 2011

This paper presents the results of a laboratory investigation on construction method of geogrid encased stone column (GESC). In order to analyze effects of load carrying capacity and geogrid deformation characteristics of GESC, a series of medium scale unconfined compression tests with different overlay methods and reduced model tests were performed. The test results show that the method of overlap provides a simple and effective method of encasement construction. It is also found that geogrid encasement construction using method of overlap has important factor which can be applied to field tests. The geogrid encasement method related to effect of reinforcement is presented by laboratory test results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.6 no.2
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• pp.10-18
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• 1988

In the three-dimensional analysis and deformation analysis of large structures, efficient is the use of the multiple method of close range photogrammetry which approaches the object distance. This study analyzes the influence of errors according to the overlap, the control points, and the object distance, to solve the problems which are raised in the multiple method. A wall-board, 7 meters by 3 meters, was used as a test field on which a total of 225 unknown points were equally disposed. The photographs with changing the overlap and object distance were taken by P-31 camera system. a total of 143 negatives are used in this study for computing 3-dimensional coordinates and its standard errors, and bundle adjustment of strips and blocks developed with on-line system is applied. In case of decreasing the number of control points, simulation error increases but actual error decreases and increases again. Due to the changed of object distances Z error represents largely compared to X, Y error, but good results in Z can be obtained by increasing the redundancy. And simulation error or actual error shows best results at the endlap of about 70%. To sum up this study, approprate arrangement of control points and overlap is meaningful, and multiple method by short object distance will be widely used to precision and deformation analysis of critical structures.

• Progress in Medical Physics
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• v.27 no.4
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• pp.203-212
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• 2016

Dose differences between three-dimensional (3D) and four-dimensional (4D) doses could be varied according to the geometrical relationship between a planning target volume (PTV) and an organ at risk (OAR). The purpose of this study is to evaluate the correlation between the overlap volume histogram (OVH), which quantitatively shows the geometrical relationship between the PTV and OAR, and the dose differences. 4D computed tomography (4DCT) images were acquired for 10 liver cancer patients. Internal target volume-based treatment planning was performed. A 3D dose was calculated on a reference phase (end-exhalation). A 4D dose was accumulated using deformation vector fields between the reference and other phase images of 4DCT from deformable image registration, and dose differences between the 3D and 4D doses were calculated. An OVH between the PTV and selected OAR (duodenum) was calculated and quantified on the basis of specific overlap volumes that corresponded to 10%, 20%, 30%, 40%, and 50% of the OAR volume overlapped with the expanded PTV. Statistical analysis was performed to verify the correlation with the OVH and dose difference for the OAR. The minimum mean dose difference was 0.50 Gy from case 3, and the maximum mean dose difference was 4.96 Gy from case 2. The calculated range of the correlation coefficients between the OVH and dose difference was from -0.720 to -0.712, and the R-square range for regression analysis was from 0.506 to 0.518 (p-value <0.05). However, when the 10% overlap volume was applied in the six cases that had OVH value ${\leq}2$, the average percent mean dose differences were $34.80{\pm}12.42%$. Cases with quantified OVH values of 2 or more had mean dose differences of $29.16{\pm}11.36%$. In conclusion, no significant statistical correlation was found between the OVH and dose differences. However, it was confirmed that a higher difference between the 3D and 4D doses could occur in cases that have smaller OVH value.