• Proceedings of the KSME Conference
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• 2000.04a
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• pp.826-830
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• 2000

Sculptured surface machining plays a vital role in the process of bring new Products to the market place. A great variety of products rely on this technology for the production of the dies and moulds used in manufacturing. And, the use or CNC machines and CAD/CAM system has become a vital parts or product development process. But, cusp is inevitable by-product in sculptured surface machining, and it is very difficult to calculate the cusp height correctly. In this study, an analytical cusp height model is proposed considering the radius of the ball end mill, radius of machined workpiece and the inclined angle of convex or concave circular surface. Experiments were performed to check the validity of this proposed model and experimental results showed that the proposed cusp model were very effective.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.795-800
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• 2000

In a parallel manipulator, there are three constraints that determine workspace: link length constraint, passive joint angle constraint, and interference among links. Generally, the link length constraint is the most dominant. The interference among links is, however, also an important parameter in designing a desired parallel manipulator. In this study, the interference among links is mathematically modeled by considering the links as a line and a cylinder of radius of twice the link radius, and a new algorithm is suggested to check if arbitrary two links interfere each other or not. The workspace of a cubic parallel manipulator is illustrated in a 2D space satisfying the three constraints.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.2
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• pp.31-42
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• 1986

The prediction of performance, exhaust emissions and EGR effect is made by the SI engine cycle simulation. In this simulation several models are employed - two zome, thermodynamic combustion, mass fraction burned, heat transfer, chemical equilibrium, chemical kinetics for NOx, laminar flame speed for ignition delay. The chemical species in burned gas considered are 13 species-CO$_{2}$, CO, $O_{2}$, H$_{2}$O, H$_{2}$,OH, H, O, N$_{2}$, NO$_{2}$, N, Ar - and the cylinder pressure, burned and unburned zone temperature and composition of gas are calculated at each crank angle through the compression, ignition delay, combustion and expansion process. To check the validity of the model, experimental study is done for measuring emissions, combustion pressure and engine output. The predicted values for pressure and emissions show qualitative agreement with the measured data and the EGR effect also shows similar tendency.

• International Journal of Aeronautical and Space Sciences
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• v.6 no.2
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• pp.17-22
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• 2005

As one of validation tool for attitude determination system, we have used various constraints using priori information which is known through base vector set up. However these conventional constraints cannot guarantee validity in terms of final solutions such as Euler angle. So we suggest attitude boundary concept to verify the final attitude solution on the flying airplane, it is based on the combination of velocity based attitude estimation technique and ambiguity resolution. we can say it can check invalid solution effectively at just one epoch without repeatability test of resolved cycle ambiguity. In this paper we show that the suggested constraint can effectively reject incorrectly resolved cycle ambiguity the conventional constraints have missed.

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.506-510
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• 2017

Based on the Jansen mechanism theory, a walking robot is developed, which is able to trace a line. In order to find the optimized legs, GL(Ground Length), GAC(Ground Angle Coefficient) and Grashof criteria are utilized in m.sketch program as well as EdisonDesign program. Many types of design are applied to sensors and controls, and the functionality is checked. Finally, a prototype line tracer robot is manufactured using aduino parts and smart boards. The prototype robot is test run to check the validity of the design, and modifications are applied to improve the performance according to each test result until the best design is achieved.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.1-27
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• 2015

This article presents a theoretical parametric analysis on the ultimate torsional behaviour of axially restrained reinforced concrete (RC) beams. This analysis is performed by using a computing procedure based on a modification of the Variable Angle Truss Model. This computing procedure was previously developed to account for the influence of the longitudinal compressive stress state due to the axial restraint conditions provided by the connections of the beams to other structural members. The presented parametric study aims to check the influence of some important variable studies, namely: torsional reinforcement ratio, compressive concrete strength and axial restraint level. From the results of this parametric study, nonlinear regression analyses are performed and some design charts are proposed. Such charts allow to correct the resistance torque of RC beams (rectangular sections with small height to width ratios) to account for the favorable influence of the axial restraint.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.300-304
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• 2006

The purpose of this paper is to simulate the collision between a KHST 3D model and an oblique truck and to investigate zigzagging phenomenon. The used train model is the deformable KHST 3D model, its velocity is 110kph, and the angle of the truck is 30 degree. In order to check lateral forces between wheels and rails, the KEYWORDs that LS_DYNA provides, *RAIL_TRACK and *RAIL_TRAIN are used.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.773-776
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• 2005

An Experiment was carried out to study deburring in frilling hole on the Inclined exit surface. Two different deburring tools, exit surface angles, materials and cutting conditions were selected to check their performance using CNC machining center. In deburring operation, there are not only flat exit surfaces but also inclined exit surfaces which is described as inclination angle. Inclination of exit surface causes a quite different burr formation when comparing with flat surface. Deburring characteristics are analyzed according to the deburring tools and cutting conditions. Several strategies for a effective deburring on inclined exit surface were proposed.

• Design & Manufacturing
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• v.15 no.3
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• pp.19-25
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• 2021

The bending process of a press die is to bend a flat blank to the required angle. There are V-bending, U-bending, Z-bending, O-bending etc. for bending processing, and the basic principle of calculating the unfolding length of die processing is used as the neutral plane length. Since the constant of the length value of the neutral surface is different depending on the type of bending, it is impossible to accurately calculate it. In particular, Z-bending processing is performed twice, and it is set on the upper and lower surfaces of the blank, and bending processing occurs at the same time as the upward and downward bending, and the elongation of the material occurs and the material increases. It is not possible to check with the calculated value, and it occurs in many cases where the mold is modified after start-up. This study aims to minimize die modification by developing a formula to calculate the development length of Z-bend.

• Computers and Concrete
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• v.28 no.6
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• pp.621-634
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• 2021

For the reliable strut-and-tie model (STM) design of disturbed regions of concrete members, structural designers must accurately determine the strength of concrete struts to check the strength conditions of a selected STM el and the anchorage of reinforcing bars in nodal zones. In this study, the author proposed a consistent numerical method for strut strength, applicable to all two-dimensional STMs. The proposed method includes the effects of a biaxial stress state associated with tensile strains in reinforcing bars crossing a strut, deviation angle between strut orientation and compressive principal stress flow, and degree of confinement provided by reinforcement. The author examined the method's validity through the STM prediction of the ultimate strengths of 517 reinforced concrete (RC) deep beams, 24 RC panels, and 258 RC corbels, all tested to failure.