• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.383-384
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• 2007

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.3
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• pp.22-31
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• 2022

Existing Finocyl grain designs assume configurations and repeat the process of configuration modification and confirmation of the requirements through burn-back analysis. Such a design increases the design fatigue of workers and has a problem of different design completeness depending on capabilities. Therefore, this study devised an optimal design method that applied genetic algorithms to the Burn-back automation analysis program to solve the problem of existing design. For stable search, variable-offset and non-drawable configuration control techniques were developed. The program performance was verified through the searching neutral and double thrust grains.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.64-70
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• 2001

In all the Rapid Prototyping (RP) techniques, the computer-aided design (CAD) model of a three-dimensional part is sliced into horizontal layers of uniform, but not necessarily constant, thickness in the building direction. Each cross- sectional layer is successively deposited and, at the same time, bonded onto the previous layer. The stacked layers form a physical part of the model. The objective of this study is to develop a software for automatic generation of unit shape part(USP) for a new RP process, Variable Lamination Manufacturing using the linear hotwire cutting technique and expandable polystyrene foam sheet as part material(VLM-S). In order to examine the applicability of the developed software to VLM-S, USPs of general three-dimensional shapes, such as an auto-shift lever knob and a pyramid shape were generated.

• Journal of the Korean Magnetics Society
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• v.20 no.1
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• pp.24-27
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• 2010

This paper presents the design optimization of a linear actuator for fast response of electromagnetic engine valve. The optimization is performed using generic algorithm which is one of global search techniques and not highly dependent on either initial conditions or constraints in the solution domain to maximize the mechanical frequency of the armature mass and valve spring stiffness for fast response of the engine valve. In the results, the mechanical frequency is improved by 30 %.

• Journal of the Korean Society for Nondestructive Testing
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• v.35 no.1
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• pp.52-60
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• 2015

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.714-719
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• 2013

A turboprop aircraft for this study is required to operate at icing condition in order that it performs its given mission. So an air intake system of the turboprop aircraft should be designed and verified not only to provide the maximum possible total pressure at engine inlet at normal flight condition, but also to include an inertial separator which protects Foreign Object Debris (FOD) like ice or snow at icing condition from entering into the engine inlet screen which can cause or lead an catastrophic engine failure like engine flame-out or severe damage. So an air intake assembly incorporating a variable geometry inertial separator has been designed and then CFD/structural analysis for the assembly was performed to see its design results. Then 35% scaled model of the air intake assembly was manufactured and wind tunnel test was done. This paper describes the detailed design results for the aerodynamic design, analysis and wind tunnel testing during the development process of the air intake assembly.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1047-1050
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• 1997

Rapid Prototyping(RP) is an efficient method for rapid design verification and trial manufacturing. In order to improve their unique characteristics according to the working principles. Variable Lamination Manufacturing process and corresponding CAD/CAM system is developed. The objective of this study is to improve dimensional accuracy of VLM-ST process, and it can be done by offset for cutting error correction, cutting path correction for sharp edge and reference shape generation. To verify the proposed algorithms, they applied to three-dimensional shapes, such as spanner and mechanical part.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.275-278
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• 2010

By changing the nozzle throat area during the operation, thrust of a pintle thruster can be adjusted easily such as a liquid propulsion. In this paper, numerical analysis was carried out for SNECMA's pintle thruster with different pintle shapes. Flow field and aerodynamic load changed drastically with pintle shapes. Bore in the pintle decreased aerodynamic load significantly.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.74-80
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• 2005

A new dimension measuring method for the measurement of diameter of an object has been developed using laser triangulation. The 3D data of an object was calculated from the 2 dimensional image information obtained by the laser stripe using the laser triangulation. The system that use existing theory can measure the diameter of hole not only in a normal plane but also ill an incline plane. However, in the existing theory, since the lens with fixed feral length was used, the area of measurement was fixed. The simplest way to solve this problem is to change distance between a CCD camera and object. Other way is to use a zoom lens having variable focal length. In this paper, the zoom lens with variable focal length was used. Therefore, we ran experiment with magnification that is optimized according to size of object using zoom lens with variable focal length.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.10
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• pp.236-242
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• 2019

Recently, scanning projects have been carried out in various construction and construction fields for maintenance purposes. The point cloud generated by the scan results is composed of a number of points representing the object to be scanned. The process of extracting the necessary information, including dimensions, from such scan data is called paradox. The reverse engineering process of modeling a point cloud as BIM involves considerable manual work. Owing to the time-consuming reverse engineering nature of the work, the costs increase exponentially when rework requests are made, such as design changes. Reverse engineering automation technology can help improve these problems. On the other hand, the reverse design product is variable depending on the use, and the kind and detail level of the product may be different. This paper proposes the G2BM (Geometry-to-BIM mapping) rule definition method that automatically maps a BIM object from a primitive geometry to a BIM object. G2BM proposes a process definition and a customization method for reverse engineering BIM objects that consider the use case variability.