• 대한전기학회논문지
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• 제43권6호
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• pp.885-895
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• 1994

In this paper, we propose the one-Ampere conductor method which is able to calculate the flux distribution conceptually and easily, and the improved winding method which suppresses space harmonics of magnetormotive force and enhances the coefficient of utilization of primary iron core in tubular linear induction motor. We carry out no-load test to verify effectiveness of proposed method and analyze characteristics by finite element method. As a result, performances are improved and propriety of primary iron core is enhanced comparing with conventional model.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.145-148
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• 2006

Schmidt hammer and ultra-sonic method are commonly used for crushed sand concrete compressive strength test in a construction field. At present, various of equations for prediction of strength are present, which have been used in a construction field. The purpose of this study is to evaluate the correlation between prediction strength by presentation equations and destructive strength to test specimen, and find out which is a suitable equation for the construction site, In this study, a strength test was carried out destructive test by means of core sampling and traditional test. Non-destructive test was conducted Schmidt hammer and ultra-sonic method, the experimental parameter were concrete age, curing condition, test method and strength level. It is demonstrated that the correlation behavior of crushed sand concrete strength in this study good due to the perform analysis of correlation between core, destructive strength and non-destructive strength.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 가을 학술발표대회 논문집(III)
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• pp.767-772
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• 1998

schumidt hammer and ultra-sonic method are commonly used for concrete compressive strength test in a construction field. At present, various kinds of equations for estimation of strength are present, which have been used in a construction field. The purpose of this study is to evaluate the correlation between estimation strength by presentation equations and destructive strength to test specimen, and find out which is a suitable equation for this construction site. In this study, a strength test was carried out destructive test by means of core sampling. Non destructive test was conducted Schumidt hammer and ultra-sonic method, the experimental parameter were concrete age, test method and strength level. It is demonstrated that the correlation behavior of concrete strength in this study good due to the performs analysis of correlation between core strength and nondestructive strength.

• Fibers and Polymers
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• 제7권4호
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• pp.420-423
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• 2006

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yam. However it's difficult to produce wool/spandex core-spun yam on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yam produced in this way has good appearance and quality by comparing with normal yam. A series of experiments were carried out to study the influence of spandex drafting ratio and yam twist factor on tensile' properties and elasticity of core-spun yams. The results indicate that core-spun yam with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3363-3369
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• 2014

최근에 건축물의 실내환경을 쾌적하고 안전하게 유지하는 데 많은 노력이 일어나고 있다. 이러한 가운데 주방에서 주로 사용되는 렌지후드에 따른 환기방식은 많이 채택되고 있다. 이에 따라 다양한 디자인의 렌지후드가 적용되고 있다. 렌지후드는 여러 가지 여건상 프레스 금형으로 제작되어 지는데 중,소량의 생산에는 경제성이 떨어진다. 이러한 문제점을 보완하는 방안이 검토되고 있는 상황에서 코어 변환에 따른 금형개발은 매우 유용하리라 판단된다. 본 연구는 금형의 core를 change core 공법으로 설계하였고, 총 4공정으로 금형제작을 수행하였다. 이런 결과로 생산기간 단축 및 모델변경이 용이한 프레스 금형을 개발하였다. 또한 시제품은 3차원 측정결과 제품 표면의 모든 영역에서 허용오차 범위(${\pm}2.00mm$)로 합격하였다.

• 디지털산업정보학회논문지
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• 제18권3호
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• pp.83-95
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• 2022

A technology can be newly formed through technological convergence achieved by the intersection of two or more technological fields. As the complexity of technology development increases, related interest is increasing. Researches have been carried out on the concept, related indicators and analysis of technology convergence including method of social networks. This paper intends to suggest an analysis method of technology convergence using social networks based on the company's possessing technologies. According to the similarity of technologies among companies, a social network was constructed and the technology convergence was analyzed using k-core, a social network subgroup method. Using the result of k-core, base and element technologies for convergence was identified with their relations. Using the suggested method, technology convergence was analyzed on real technology data of defense-industry companies. When the minimum technology similarity is 0, the overall technology convergence relations between technology elements can be identified. In the scope of data in this paper, technologies of defense S/W, aircraft structure and structural materials are identified as important base technology for convergence.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.618-623
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• 2000

In order to increase the porductivity of electrical parts, manufacturing processes using progressive dies have been widely used in the industry. Motor cores have been fabricated using progressive stacking die with the lamination procedure for better electro-magnetic property. for the proper design of a process, a prediction of the process is required to obtain many design parameters. In this work, rigid-plastic finite element analysis is carried out in order to simulate the lamination this work, rigid-plastic finite element analysis is carried out in order to simulate the lamination process of the motor core. The effects of the embossing depth and the amount of deviation are investigated and compared with experiments. The forming process can then be predicted successfully from the results of analyses, which enables to design appropriately the die and the process.

• 소성∙가공
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• 제32권1호
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• pp.12-19
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• 2023

The armature core is a part responsible for the skeleton of the steering wheel. Currently, in the case of commercial trucks, the main parts of the parts are manufactured separately and then the product is produced through welding. In the case of this production method, quality and cost problems of the welded parts occur, and an integrated armature core made of magnesium alloy is used in passenger vehicles. However, in the case of commercial trucks, there is no application case and research is insufficient. Therefore, this study aims to develop an all-in-one armature core that simultaneously applies a magnesium alloy material and a die casting method to reduce the weight and improve the quality of the existing steel armature core. The product was modeled based on the shape of a commercial product, and finite element analysis (FEA) was performed through Ls-dyna, a general-purpose analysis program. Through digital image correlation (DIC) and uniaxial tensile test, the accurate physical properties of the material were obtained and applied to the analysis. A total of four types of compression were applied by changing the angle and ground contact area of the product according to the actual reliability test conditions. analysis was carried out. As a result of FEA, it was confirmed that damage occurred in the spoke area, and spoke thickness (t_spoke), base thickness (t_base), and rim and spoke connection (R) were designated as design variables, and the total weight and maximum equivalent stress occurring in the armature core We specify an objective function that simultaneously minimizes . A prediction function was derived using the sequential response surface method to identify design variables that minimized the objective function, and it was confirmed that it was improved by 22%.

• 전산구조공학
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• 제4권2호
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• pp.103-110
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• 1991

컴퓨터의 제한된 코어메모리로 대형문제를 해결하기 위하여 디스크를 마치 메모리처럼 사용할 수 있는 가상 메모리 데이타베이스 기법을 개발하였다. 이 기법과 아울러 최대 가용코어메모리를 작동시키는 방식을 사용하여 유한요소 해석시 흔히 발생하는 스카이라인 형태로 저장된 대칭통산행예(Sparse Symmetric Matrix)에 대한 매우 효과적인 코어 내 및 코어 외 직립방정식의 해법을 개발하였다. 제안된 방법은 다른 코어 외 해법에 비해 알고리즘 및 코딩이 매우 간단하여 계산효율을 상당히 향상시켰다. 해석예에서는 제안된 방법을 사용하여 대규모 구조해석 문제를 메모리 용량이 작은 소형컴퓨터에서 대단히 효율적으로 해결하였음을 보여주었다.

• Steel and Composite Structures
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• 제51권1호
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• pp.73-91
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• 2024

This paper has focused on presenting vibration analysis of trapezoidal sandwich plates with a damaged core and FG wavy CNT-reinforced face sheets. A damage model is introduced to provide an analytical description of an irreversible rheological process that causes the decay of the mechanical properties, in terms of engineering constants. An isotropic damage is considered for the core of the sandwich structure. The classical theory concerning the mechanical efficiency of a matrix embedding finite length fibers has been modified by introducing the tube-to-tube random contact, which explicitly accounts for the progressive reduction of the tubes' effective aspect ratio as the filler content increases. The First-order shear deformation theory of plate is utilized to establish governing partial differential equations and boundary conditions for the trapezoidal plate. The governing equations together with related boundary conditions are discretized using a mapping-generalized differential quadrature (GDQ) method in spatial domain. Then natural frequencies of the trapezoidal sandwich plates are obtained using GDQ method. Validity of the current study is evaluated by comparing its numerical results with those available in the literature. After demonstrating the convergence and accuracy of the method, different parametric studies for laminated trapezoidal structure including carbon nanotubes waviness (0≤w≤1), CNT aspect ratio (0≤AR≤4000), face sheet to core thickness ratio (0.1 ≤ ${\frac{h_f}{h_c}}$ ≤ 0.5), trapezoidal side angles (30° ≤ α, β ≤ 90°) and damaged parameter (0 ≤ D < 1) are carried out. It is explicated that the damaged core and weight fraction, carbon nanotubes (CNTs) waviness and CNT aspect ratio can significantly affect the vibrational behavior of the sandwich structure. Results show that by increasing the values of waviness index (w), normalized natural frequency of the structure decreases, and the straight CNT (w=0) gives the highest frequency. For an overall comprehension on vibration of laminated trapezoidal plates, some selected vibration mode shapes were graphically represented in this study.