• Transactions of Materials Processing
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• v.17 no.2
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• pp.130-134
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• 2008

Resource and energy saving is a very important practice for the future as well as for today. Weight saving of structural parts, which are formed by extrusion, plays a key role in manufacturing field. The cross-sections of extruded parts with industrial aluminum are constant in the axial direction by conventional extrusion method. Especially, these aluminum parts used and manufactured in the car industry need other processes to vary the cross-section in the axial direction. However, applications of these parts are often limited by high cost. If the cross-section of the parts is variable by only extrusion with newly developed method, the application of extruded aluminum parts will actually increase. Therefore, a new CNC extruder that can control the section area of a car part was invented for the first time in the nation. Using the extrusion machine, the experiment was performed to validate its workability during the variable section extrusion process. Also, numerical analysis was carried out to investigate the flow mode with different speeds of main ram and various pocket shapes of a die-set in the variable section extrusion process.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.581-590
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• 2010

This study introduces a layered sectional analysis for a PSC girder with a vaiable cross section and curved tendons. To consider the shear equilibrium at a concrete layer with curved tendons, the shear stress distribution has been computed at each section. In addition, to improve the convergence to the solution, a system identification technique is newly adopted in the solution process for strain computation. To examine the feasibility of the proposed approach, a static load test has been conducted for a full scale PSC girder with variable cross section. The prediction shows a good agreement with experiment. It is seen that a uniform cross section has the same moment capacity with a variable cross section while the variable cross section has more shear capacity than the uniform cross section. It is also noted that the maximum displacement of a variable cross section is a little smaller than a uniform cross section.

• Korean Journal of Computational Design and Engineering
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• v.14 no.4
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• pp.234-241
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• 2009

The use of aluminum parts in automobile structuraI applications has increased in an effort to reduce the weight of cars and hence improve fuel economy. But Aluminum bar, I-beam and channels need other processes to vary the cross section in the axial direction. Thus, applications of these parts are limited by high cost. If the cross section of the part is variable by using only extrusion, application of extruded bar, I-beam and channels will increase in the Aluminum industries. In this paper, we propose the variable-shape extrusion process which can control the thickness of Aluminum bar. And we can calculate the speed of center ram by varying the cross section in the extrusion to control the thickness of Aluminum bar.

• Structural Engineering and Mechanics
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• v.68 no.6
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• pp.713-720
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• 2018

In this paper a new numerical method to determine the elastic curve of the simply supported beams of variable cross-section is demonstrated. In general case it needs to solve linear or small nonlinear second order differential equations with prescribed boundary conditions. For numerical solution the initial values of the slope and the deflection of the end cross-section of the beam is necessary. For obtaining the initial values a lively procedure is developed: it is a special application of the shooting method because boundary value problems can be transformed into initial value problems. As a result of these transformations the initial values of the differential equations are obtained with high accuracy. Procedure is applied for calculating of elastic curve of a simply supported beam of variable cross-section. Results of these numerical procedures, analytical solution of the linearized version and finite element method are compared. It is proved that the suggested procedure yields technically accurate results.

• Journal of the Korean Geosynthetics Society
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• v.15 no.4
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• pp.89-96
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• 2016

Compressive axial behavior of the variable cross-section soft ground reinforced foundation is investigated from the field load test results at ${\bigcirc}{\bigcirc}$ construction site in Incheon city. Variable cross-section soft ground reinforced foundation is a type of partial-displacement pile formed by mixing bidding material with in situ soils to obtain a rigid and strong variable cross-section column in a relatively soft ground. The foundations are usually constructed as a group; however in this study, only single foundation was installed and tested under compressive axial load on foundation head. For the comparison of the variable cross-section soft ground reinforced foundation axial behavior, behavior of typical Pretensioned spun high strength concrete (PHC) pile constructed on a relatively soft ground near the surface was analyzed. It was concluded that variable cross-section soft ground reinforced foundation efficiently resists against axial load with sufficient stiffness and strength within a considerable range of axial load magnitude.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.858-863
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• 2003

In the practical engineering fields, the horizontally curved beams are frequently erected as the major/minor structural components. The effects of both variable curvature and variable cross-section on structural behavior are very important and therefore these effects should be included in structural analyses. From this viewpoint, this paper deals with the free vibrations of horizontally curved beams with variable curvature and variable cross-section. In this study, the parabola as the curvilinear shape and stepped beam as the variable cross-section are considered. The ordinary differential equation governing free vibrations of such beams are derived. For calculating the natural frequencies, the governing equations are solved by numerical methods. The Runge-Kutta and Determinant search Methods are used for integrating the differential equations and for calculating the natural frequencies, respectively. With regard to numerical results, the relationships between frequency parameters and various beam parameters are presented in the forms of Table and Figures.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.1
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• pp.135-147
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• 2000

Section design of vehicle structure has been developed by two methods. One is the section property method which uses section property as a design variable. This method shows the tendency of an optimum section approximately. The other method is the section shape method which utilizes geometric parameter of section as a design variable. Practical solutions are obtained by this method. However, it is very expensive for large-scale problems due to the large number of geometric parameters. These two methods are compared through several sample problems. The finite element method is used for the structural and sensitivity analyses. The results are analyzed based on the number of function evaluations, the quality of cost function, the complexity of programing, and etc. The applications of both methods are also discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.643-644
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• 2009

• Journal of Korean Society of Steel Construction
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• v.16 no.1 s.68
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• pp.81-89
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• 2004

The vibration analysis of the circular arch as a member of a structure has been an important subject of mechanics due to its various applications to many industrial fields. In particular, circular arches with variable cross section are widely used to optimize the distribution of weight and strength and to satisfy special architectural and functional requirements. The Generalized Differential Quadrature Method (GDQM) and Differential Transformation Method (DTM) were recently proposed by Shu and Zou, respectively. In this study, GDQM and DTM were applied to the vibration analysis of circular arches with variable cross section. The governing equations of motion for circular arches with variable cross section were derived. The concepts of Differential Transformation and Generalized Differential Quadrature were briefly introduced. The non-dimensionless natural frequencies of circular arches with variable cross section were obtained for various boundary conditions. The results obtained using these methods were compared with those of previous works. GDQM and DTM showed fast convergence, accuracy, efficiency, and validity in solving the vibration problem of circular arches with variable cross section.

• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.34-38
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• 2010

An analytical solution procedure for the dynamic response of beams with variable properties is developed by using an asymptotic solution and the Green's function. This asymptotic closed form solution is derived for the transverse vibration of beams under the assumption of slowly varying properties, such as mass, cross-section, tension etc., along the beam length. However, this solution is still found to be very accurate even in the case of large variation, such as step change in cross-section, mass, and tension. Therefore, this derived asymptotic closed form solution and the Green's function can be easily applied to find dynamic responses for various kind of beam vibration problems.