• Structural Engineering and Mechanics
• /
• v.73 no.5
• /
• pp.599-612
• /
• 2020

A combination of a gravity wall and an anchor beam is widely used to support the high soil deposit on rock mass. In this study, two groups of shaking table test were performed to investigate the responses of such combined retaining structure, where the rock masses were shaped with a flat surface and a curved surface, respectively. Meanwhile, the dynamic numerical analysis was carried out for a comparison or an extensive study. The results were studied and compared between the combined retaining structures with different shaped rock masses with regard to the acceleration response, the earth pressure response, and the axial anchor force. The acceleration response is not significantly influenced by the surface shape of rock mass. The earth pressure response on the combined retaining structure with a flat rock surface is more intensive than the one with a curved rock surface. The anchor force is significantly enlarged by seismic excitation with a main earthquake-induced increment at the first intensive pulse of Wenchuan motion. The value of anchor force in the combined retaining structure with a flat rock surface is generally larger than the one with a curved rock surface. Generally, the combined retaining structure with a curved rock surface presents a better seismic performance.

• Journal of Ocean Engineering and Technology
• /
• v.32 no.2
• /
• pp.106-115
• /
• 2018

The forward and afterward parts of ships and offshore structures are designed to improve the fuel consumption performance. These are made of curved plates with a large thickness. If a fabricated curved plate has some dimensional errors, a lot of additional cost is incurred in the assembly process. Thus, an accurate dimensional assessment is very important for fabrication. In this paper, we propose an assessment method for the dimensional quality management of curved plates. This can be applied to data measured using a variety of three-dimensional instruments, with boundary measurement points automatically classified and sorted to create a measurement surface. The assessment is evaluated after matching the CAD surface and the measured surface considering constrained conditions. The fabrication assessment is evaluated as a probability of how much the tolerance is satisfied.

• Advances in nano research
• /
• v.5 no.1
• /
• pp.35-47
• /
• 2017

This paper deals with free vibration analysis of nanosize rings and arches with consideration of surface effects. The Gurtin-Murdach model is employed for incorporating the surface effect parameters including surface density, while the small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. An analytical Navier solution is presented to solve the governing equations of motions. Comparison between results of the present work and those available in the literature shows the accuracy of this method. It is explicitly shown that the vibration characteristics of the curved nanosize beams are significantly influenced by the surface density effects. Moreover, it is shown that by increasing the nonlocal parameter, the influence of surface density reduce to zero, and the natural frequency reaches its classical value. Numerical results are presented to serve as benchmarks for future analyses of nanosize rings and arches.

• International Journal of Railway
• /
• v.7 no.2
• /
• pp.57-63
• /
• 2014

This paper presents the optimization of suspension characteristics under the condition of curved track railway vehicles. Reducing lateral acceleration on curved track is an issue for high-speed railway vehicles. In terms of curved track running environments, reducing the lateral vibration of railway vehicles is critical to safety and curving performance. The properties of lateral damping and stiffness of both primary and secondary suspension show effect on wheel-set, bogie and car-body. Analysis for reducing the lateral vibration of rail vehicles with respect to the characteristics of both primary and secondary suspension has been developed using ADAMS/Rail. Response Surface Method has been chosen for the purpose of verifying correlation effects among design parameters. Also, this paper suggests the method for designing optimal suspension of railway vehicles on curved track. The optimization result indicates decrement of lateral acceleration on wheel-set by 3% and bogie by 1% on curved track. Finally, this paper comes to the conclusion that suspension system of railway vehicle (KTX I) is properly designed when regarding lateral vibration of railway vehicle on diverse curved track condition.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.10 no.1
• /
• pp.95-101
• /
• 2017

In natural images, there is generally locality, and the values of adjacent pixels are similar. It is possible to estimate the curved surface characteristics of the original image using adjacent pixels having similar pixel values. In this paper, after precisely estimating the characteristics of the curved surface existing in the image, interpolation values are obtained so as to faithfully reflect the estimated characteristics of the curved surface, We propose an effective image enlarging method that generates an enlarged image using the obtained interpolation values. The image enlarged by the proposed method maintains the curved surface characteristics of the original image, and thus the image quality of the enlarged image is improved. Experimental results show that the image quality of the proposed method is superior to that of the conventional techniques.

• Journal of the Korean Society for Precision Engineering
• /
• v.33 no.10
• /
• pp.875-880
• /
• 2016

In this study, we proposed an effective and simple way to directly generate wrinkle patterns on a curved surface. A curved surface was prepared using a 3D printer and an UV (Ultraviolet)-lighting system was utilized to weakly polymerize the UV-curable thin resin layer coated on the surface, resulting in a gradient of material properties in the layer thickness. Subsequently, a thermal curing process was conducted to generate microscale wrinkles by compressive forces that were generated during complete curing. Wrinkle shapes from 5, 15, 25 sec of UV-light exposure were compared. With increasing UV-exposure, the line-width of wrinkles became thicker due to much higher strength of skin zone. The results indicated that the proposed fabrication process could be utilized for surface modification in diverse research fields.

• Fashion & Textile Research Journal
• /
• v.19 no.5
• /
• pp.635-645
• /
• 2017

The industry of character toys is increasing and new characters are constantly being developed. However, the development of 2D cover patterns for toys is time-consuming due to frequent pattern modifications made through trial and error. Studies are now underway to obtain 2D clothing patterns from 3D body data, however, little research has been done on 2D pattern of character toys. This study suggests efficient guidelines to develop 2D cover patterns with a reasonable accuracy and processing time. Two 3D models of a dog and rabbit were used to develop 2D cover patterns. Independent variables of this study are set as 3 levels of triangle area (small, medium, and large) that influence the efficacy of 3D and 2D pattern development. The determination of the appropriate triangular area was based on the area and shape change of the 2D pattern. A medium or large triangle area was shown to be suitable for a character dog with a smooth curved surface. However, the appropriate triangle area was small if the characteristics of the curved surface are complicated as in the case of rabbit. The head of a dog (a double-curved surface) and the curved forepaw of a rabbit (a triangular area) should be small when the characteristics of the curved surface (such as the hind leg of a rabbit having a large convex surface and a small surface area) are complicated. Grouping by 3D surface characteristics could be a suitable guideline for the triangle area selection.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2013.05a
• /
• pp.236-237
• /
• 2013

In recent years, the use of glass applied to curtain wall as a building facade material has increased in our nation. However, the non-tempered curved double glass is very easy to broke because it is difficult to guarantee the quality in process of making it into double glazing. So, it is more vulnerable to thermal breakage than tempered double glass. In this paper, surface temperature difference on curved double glazing was compared to that of heat strengthened glass and flat glass by conducting thermal breakage experiments. As a result, flat single glass was broken at temperature difference of 100~140 degrees but curved double glazing was broken at that of 40~60 degrees. Therefore, it was concluded that curved double glazing is more vulnerable than flat double glazing to thermal breakage, and it should be considered the possibility of thermal breakage when curtain wall glazing is applied as a building facade material.

• Water for future
• /
• v.25 no.3
• /
• pp.87-96
• /
• 1992

Hydraulic characteristics such as velocity, surface level and flow pattern in the curved channel are analyzed by model experiment, where model is scaled down by 1:20 for prototype channel containing side branch and curved section. The withdrawal of channel flow from channel is analyzed to find the effect on the curve section. The numerical scheme for shallow water equation using ADI method is verified through the comparison of hydrauric characteristics by experiment with that by numerical analysis in the side section of model channel. The comparison of numerical results with experimental data shows that velocity, surface level and flow pattern agree well for overall channel. Because fo the relative contraction of cross section in the curved section caused by rectangular system, the velocity calculated by numerical analysis is faster in curved section than that from experiment, which can be improved using finer spatial grid in curved section. The characteristics of the curved section such that the surface level is higher in the outer zone of curved section and the velocity is faster in the inner zone are well simulated by both experiment and numerical analysis. The effect of side branch reaches within the zone of the curved section.

• Journal of the Korean Society for Precision Engineering
• /
• v.17 no.4
• /
• pp.69-80
• /
• 2000

Generally, die polishing is a lime consuming process, resulting in 30∼50％ of the whole die manufacturing time. However, die polishing has not been automated yet, since it needs a great deal of experience and skill. This paper describes a new development of automated system for die polishing and focuses on the successful achievements of the element techniques to realize from hand skill to automation, as followings: (1) The 5 axes polishing system by the aid of robot with 2 degrees of freedom, is developed for the application of curved surface die. (2) The CAM system realizes a 5 axes tool path control for polishing and measuring. (3) The conductive elastic tool is able to meet curved surfaces of die and gives a high efficient and quality polishing characteristics. (4) The surface roughness measurement device with noncontact laser is developed and has a high reliability without surface damage.