• 한국의류학회지
• /
• 제46권5호
• /
• pp.910-926
• /
• 2022

Suitability for the human body, freedom to move and thermal insulation are important design considerations in military clothing. This study investigates the performance and wearer-satisfaction of the functional inner winter uniform currently used in Korea; it is hoped that our data can inform the development of a future version. Interviews were conducted, in which the participants suggested various improvements. The uniforms were mainly worn for guard duty or as daily attire in cold weather. The participants chose how many layers to wear according to the current situation, rather than sticking to the layering recommended in the manual. Layering choices did not significantly affect combat efficiency but were found to affect wearers' comfort. Wearers' satisfaction was found to depend on the convenience of the clothing, whether it was in the appropriate size, freedom to move and thermal insulation. Also, this study suggests a problem with the current size system, as the analysis of size distribution, across all sizes, the range of current production is insufficient to cover the demand.

• 설비공학논문집
• /
• 제28권5호
• /
• pp.171-177
• /
• 2016

Plate heat exchangers have been widely used in various fields because of their high heat transfer coefficients, small area of installation, and ease of maintenance compared to other heat exchangers. However, when plate heat exchanger is used for a long time, leak can occur due to inner crack. Therefore, it is important to understand the inner flow characteristics in plate heat exchangers. In this study, the inner flow characteristics and flow rate of plate heat exchanger were evaluated using various flow directions, pin-hole sizes, and Reynolds numbers. In downflow, initially most water flowed to the opposite of the inlet due to distribution region. Then it gradually had a uniform distribution due to chevron configuration. In upflow, it had a uniform flow consistently due to the dominant gravity effect. As the Reynolds number increased, the leak rate was decreased due to the inertia effect regardless of the flow direction.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2006년도 춘계학술대회 논문집
• /
• pp.295-299
• /
• 2006

The inner-structure bonded(ISB) sheet metal is defined as a composite sheet metal which has middle layer of truss-structure between two skin sheets. The characteristics such as ultra-light weight, high rigidity, high strength, etc are required especially for automobile parts. The characteristic of ISB sheet metal depends on inner-structure pattern or method of bonding. Pyramid type of crimped expanded metal is used for inner-structure and both of resistance welding and adhesive bonding are applied to make a specimen. As a result of compression test, it is appeared that forming limit is 10% reduction in thickness under a load of 8kgf per unit element(one inner-structure). In case of uniaxial tensile test the non-uniform surface integrity rather than the buckling of inner-structure happened at a load of 450kgf, which indicates elongation of 7.2% and thickness reduction of 13%. The eye-inspection method was applied to examine the defects occurring on the specimen during stretch forming. In case of biaxial stretch forming only the non-uniform deformation on the surface of a skin sheet could be observed. The forming limit in stretching of ISB sheet metal with the hemi-spherical punch of 150mm in diameter was 3mm in forming depth and 5% reduction in thickness.

• 대한수학회논문집
• /
• 제19권1호
• /
• pp.53-62
• /
• 2004

A result of Hardy and Littlewood relates Holder continuity of analytic functions in the unit disk with a bound on the derivative. Gehring and Martio extended this result to the class of uniform domains. We call it the Hardy-Littlewood property. Langmeyer further extended their result to the class of John disks in terms of the inner length metric. We call it the Hardy-Littlewood property with the inner length metric. In this paper we give several properties of a domain which satisfies the Hardy-Littlewood property with the inner length metric. Also we show some results on the Holder continuity of conjugate harmonic functions in various domains.

• 소성∙가공
• /
• 제8권6호
• /
• pp.612-619
• /
• 1999

Internal and external defects of an inner pulley for automobile air conditioner are investigated in this study. Inner pulley is a part of compressor clutch assembly of automobile air conditioner. In cold forging of inner pulley, the design requirement are to keep the same height of the inner rib and outer one and to make uniform distribution of hardness in the forged product. At the end of the forging of inner pulley, the piping defect as an external defect begins to form at the back center of the billet. The internal crack as an internal defect also occur at the adiabatic shear band which usually has maximum ductile fracture value. It is important to predict when the internal and external defects occur during the deformation process, in order to minimize the amount of discard that is generated. The finite element simulations are applied to analyze the defects. The validity of the computational results are examined by experiments. These computational results are in good agreement with the experimental ones.

• 대한기계학회논문집
• /
• 제11권3호
• /
• pp.479-487
• /
• 1987

본 연구에서는 액적들의 분포상태가 집단연소의 특성에 미치는 영향을 규명하 기 위하여 김의 비정상 집단연소모델에 비균일 액적크기분포와 수밀도분포를 고려한 비균일분포 집단연소모델을 구성하여 이론적으로 해석하였다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1996년도 자동차부품 제작기술의 진보
• /
• pp.23-33
• /
• 1996

Forging of an inner pulley for compressor clutch assembly of car air conditioner is investigated in this study. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and the outer one, and to make uniform the hardness distribution in the forged product. Using the rigid-plastic finite element simulation, we design the optimal process conditions, which has a performing operation. The forged pulley is investigated by checking the hardness distribution and it is noted that the distribution has improved to be even and high enough for industrial application.

• 한국자동차공학회논문집
• /
• 제5권4호
• /
• pp.199-206
• /
• 1997

The inner pulley is an automobile component used as air conditioner clutch assembly. In cold forging of inner pulley, the design requirements are to keep the same height of the inner rib and outer one, and to make uniform the hardness distribution in the forged product. In industry, the design of forging processes is performed based on experience-oriented technology, that is, designers experience and expensive trial and error. Using the rigid-plastic finite element simulations. we design the optimal process conditions, which has a preforming operation. Also the final product configuration of forging has to be designed again in view of metal flow involved in the operation, derived from the finite element simulations. The forged pulley is investigated by checking the hardness distribution and it is noted that distribution has improved to be even and high enough for industrial application.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1995년도 춘계학술대회논문집
• /
• pp.62-70
• /
• 1995

The inner pulley is automobile component used as airconditioner clutch assembly. in cold forging of the inner pulley . the design conditions are the same between inner length and outer length, the uniform hardness and the no shape change in inner fillet radius due toa piercing. In industries, the design of forging processes is performed based on an experience-oriented technology, that is, designer's experiences and expensive trial and error. Using the rigid -plastic finite element simulation, we propose the optimal process conditons and design of preform or redesign of final product shape without defects prodicted by metal flow, distribution fo strain, forging load during forging processes form initial workpiece to final product.

• 대한기계학회논문집
• /
• 제13권5호
• /
• pp.1012-1022
• /
• 1989

본 연구에서는 열원인 내관의 온도가 불균일한 경사진 동심환상공간에서의 열전달 특성을 $R_{a}$ =3*$10^{4T,P}$1r=7.0, 내외관의 반경비 0.6일 때 경사각도 0。,30。그리고 60。에 대하여 3차원 수치해석으로 연구하였으며 균일온도분포인 경우 와 비교 고찰하였다.