• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1631-1636
• /
• 2004

The supersonic impinging jet has been extensively applied to rocket launching system, gas jet cutting control, gas turbine blade cooling, etc. In such applications, wall temperature of an object on which supersonic jet impinges is a very important factor to determine the performance and life of the device. However, wall temperature data of supersonic impinging jets are not enough to data. The present study describes an experimental work to measure the wall temperatures of a vertical flat plate on which supersonic, dual, coaxial jet impinges. An Infrared camera is employed to measure the wall temperature distribution on the impinging plate. The pressure ratio of the jet is varied to obtain the supersonic jets in the range of over-expanded to moderately under-expanded conditions at the exit of coaxial nozzle. The distance between the coaxial nozzle and the flat plate was also varied. The coaxial jet flows are visualized using a Shadow optical method. The results show that the wall temperature distribution of the impinging plate is strongly dependent on the jet pressure ratio and the distance between the nozzle and plate.

• Steel and Composite Structures
• /
• v.25 no.2
• /
• pp.197-207
• /
• 2017

In this paper, Coriolis effect on vibration behavior of a rotating rectangular plate made of functionally graded (FG) materials under thermal loading has been investigated. The material properties of the FG plate are supposed to get changed in parallel with the thickness of the plate and the thermal properties of the material are assumed to be thermo-elastic. In this research, the effect of hub size, rotating speed and setting angle are considered. Governing equation of motion and the associated boundary conditions are obtained by Hamilton's principle. Generalized differential quadrature method (GDQM) is used to solve the governing differential equation with respect to cantilever boundary condition. The results were successfully verified with the published literatures. These results can be useful for designing rotary systems such as turbine blades. In this work, Coriolis and thermal effects are considered for the first time and GDQM method has been used in solving the equations of motion of a rotating FGM plate.

• Journal of Mechanical Science and Technology
• /
• v.14 no.1
• /
• pp.1-10
• /
• 2000

This work shows that it is possible to obtain information about more than one parameter from acoustic field information. A variety of ultrasonic Lamb wave modes were utilized to reconstruct thickness and density of an isotropic plate. An image reconstruction of one parameter (thickness of a plate) was carried out for four cases, i.e., the lowest symmetrical and anti symmetrical modes, and the fastest symmetrical and anti symmetrical Lamb waves among multiple modes. For two parameter reconstructions (thickness and density), the image processing was performed using the lowest symmetrical and antisymmetrical modes simultaneously. In this work, a modified version of algebraic reconstruction technique (ART), which is a form of finite-series expansion method, was employed to reconstruct the ultrasonically computed tomographic images. Results from several sample geometries are presented.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1569-1576
• /
• 2011

To install heavy structures in the railway bridges, crane methods or launching methods using temporary structure have been applied. These methods are uneconomical because working yard is required, temporary cut of rail system, etc. In this study, various construction methods has been developed which are suitable to the filed conditions. In the case of simple span structure like plate girder bridges, the girder is loaded to troy system at the working yard and then transferred to the working place. To lift and lower the girder system, a new transfer system was developed. Different methods each for simple span bridge girder and long span girder were developed and detailed work procedures were proposed. Using these methods, the heavy structures can be installed with simple and safe work procedures and the construction cost and duration can be reduced.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• v.11 no.1
• /
• pp.31-34
• /
• 2006

Purposes of this research are convenience of manufacture, quality sophistication and reduction of a/s' ratio by that improve several shortcomings of existing steel housing The Housing of head is changed existent steel housing to ABS (acrylonitrile butadiene styrene) copolymer housing and its shape is changed. It does not need that paint housing by paint. so We may not care scar at storage or manufacture. The fast work speed and A/S is possible by combining a safety plate and a housing by volt and spring washer. When disjoint head part, there is no damage of safety plate and housing. Noise is disappeared by resonance phenomenon in early rpm at motor moving. When neck part of housing and a middle pipe are connected by drill nasa, the work is easier Also, there is sense of security little more catching motor in housing The improvement accomplished much improvements including light weight of head part.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.2
• /
• pp.367-375
• /
• 1990

A data structure representing 3-D objects was designed for the personal computer. It is very simple to be used in the personal computers which have small memory and low speed. A homogeneous transformation for developing 3-D objects was derived. Each developing procedure consists of five transformations : one translational-three rotational-one translational. Developing a solid is a creative work. So the results of developing vary with the order of surfaces to be developed. One method to reduce the length of seam was considered. The programs used in this study were written in Pascal and Assembly and a modeller that generates 3-D primitives was included. This program is an interactive dual-screen system. While all the menus in Korean are displayed at the monochrome monitor, the development figures with projective views are drawn at the color monitor. The program has wide applications for plate works.

• Steel and Composite Structures
• /
• v.48 no.6
• /
• pp.709-725
• /
• 2023

This paper uses a new type of deformation theory to establish the free vibration and static buckling equations of nanoplates resting on two-parameter elastic foundations, in which the flexoelectric effect is taken into account. The proposed approach used in this work is not only simpler than other higher-order shear deformation theories but also does not need any shear correction coefficients to describe exactly the mechanical responses of structures. The reliability of the theory is verified by comparing the numerical results of this work with those of analytical solutions. The results show that the flexoelectric effect significantly changes the natural frequency and the critical buckling load of the nanoplate compared with the case of neglecting this effect, especially when the plate thickness changes and with some different boundary conditions. These are new results that have not been mentioned in any publications but are meaningful in engineering practice.

• Transactions of Materials Processing
• /
• v.9 no.4
• /
• pp.372-378
• /
• 2000

A process model including the effects of both the texture development and ductile damage evolution In plane strain rolling is presented. In this process model, anisotropy from deformation texture and deterioration of mechanical properties due to growth of micro voids are directly coupled Into the virtual work expressions for the momentum and mass balances. Special treatments in obtaining the initial values of field variables in the nonlinear simultaneous equations for the anisotropic, dilatant viscoplastic deformation are also given. Mutual effects of the texture development and damage evolution during plate rolling are carefully examined in terms of the distribution of strain components, accumulated damage, R-value as well as yield surfaces.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.10a
• /
• pp.409-416
• /
• 2001

The present work is concerned with the development of new variable-node Mindlin plate bending elements. The proposed variable-node elements pass the patch tests, do not show spurious zero-energy modes, and do not produce shear locking phenomena. It is also shown that the elements produce reliable solutions through numerical tests for standard benchmark problems.

• Journal of Coastal Disaster Prevention
• /
• v.4 no.3
• /
• pp.111-118
• /
• 2017

In this study, pull box members were designed by finite element analysis of a steel plate covering a pull box to secure its safety on the landing pier dedicated to the large research survey ship. It was assumed that the maximum load is due to the 250 tonf class crane used for unloading work when the working environment in the upper part of the landing pier was considered. The safety of the pull box was evaluated by the comparison between the yield strength of the steel plate and the result of stress analysis on the steel plate due to the crane load. It was found that the stress at the plate from the crane load exceeded the yield strength of the steel(205MPa) when the upper part of the pull box was protected by a $1950{\times}1950mm$ steel plate cover. In order to compensate for this, a concrete filled steel tube(CFT) column with a diameter of 150 mm and a steel thickness of 10 mm was reinforced at the center of the plate, and the finite element analysis was carried out. However, the maximum stress at the steel plate was higher than the yield strength of the steel in some load cases so that it was tried to find appropriate thickness of the steel plate and diameter of the CFT columns. Finally, the analysis results showed that the safety of the pull box was secured when the thickness of the steel plate and the diameter of the CFT column were increased to 30mm and 180mm, respectively.