• 대한가정학회지
• /
• 제34권2호
• /
• pp.43-55
• /
• 1996

The purpose of this study was to investigate the slacks pattern making on the movement-fitness of the knee region. The experimental items were divided into the lower limb movement (M1~M5) and slacks pattern designs (4 : basic pattern, in-pleats, side-pleats, seam-line increase). This study was done by clothing pressure test, sensory evaluation test and the difference shape-transformation of wearing-slacks. The summarized finding resulted from experiments and investigation are suggested as follows ; First, the clothing pressure test showed that the order of clothing pressure in the movement was the rabbit leap movement (M3), the sit on knees (M4), the nobleman sitting (M5), the sit on chair (M2) from the highest to the lowest. In the comparison of clothing pressure tested by blocks of lower-limb, center front knee region shows the highest of 300g/cm2. In it by constructional methods, the clothing pressure of in-pleats, side-pleats methods shows lower than basic pattern, hem-line increase methods. Also in comparison of the two methods, in-pleats method shows lower than side-pleats method. Second, by the sensory evaluation test based on the lower-limb movements and constructional methods of slacks, it was found that the functional factor score of the rabbit leap movement was also the waist, hip, knee region was the lowest in all blocks. And in the comparison of constructional methods, in-pleats method was the highest in all methods. Third, in consideration of the difference in the shape-transformation of wearing-slacks on the movement-fitness, pleats pattern design methods showed that the ratio of shape-transformation was lower than basic on seam-line increase methods. But the difference of the side-pleats and in-pleats methods was litle. According to these investigation, the slacks pattern making caused by movement-fitness on the knee region, in-pleats design method was the functional slacks pattern.

• Tribology and Lubricants
• /
• 제28권4호
• /
• pp.153-159
• /
• 2012

Tapered roller bearings are widely used in high axial-load and radial-load applications. In this study, a numerical analysis is performed to study a finite line contacts EHL problem between a tapered roller and raceway in tapered roller bearings. Converged solutions are obtained for moderate load and material parameters using a finite difference method with non-uniform grids and the Newton-Raphson method. The contours and sectional plots of pressure distribution and film shape are compared. The pressure distribution and film shapes near both ends of the roller are very different from those in the central part and are transversely asymmetric. The maximum pressure and absolute minimum film thickness always occur at the small end of the roller.

• 기술사
• /
• 제15권1호
• /
• pp.7-13
• /
• 1982

지하통신용 케이블 보호용 관로로 사용되는 합성수지관의 안전수행문제는 점차 중요성이 인식되어지고 있어 이를 검토하기 위하여 유형별에 의한 역학적 실험을 실시하였다. 그 결과 본 연구에서는 매설 파이프가 받는 토압과 수압을 실험치와 이론치로 서로 비교하여 보았고 매설깊이 별에 의한 총압력을 계산하여 적정한 매설 보건을 추정하였으며 또한 재료 특성을 파악하여 충격효과 및 변형에 대한 두께와의 관계를 알았다.

• 한국기계가공학회지
• /
• 제6권4호
• /
• pp.81-85
• /
• 2007

A safety valve is used for protecting the pressure vessel and facilities by discharging the operating fluid into the valve from the accident when the pressure is over the designated value. The fluid is sulfurous acid and nitric acid. etc. in the semi-conductor assembly line. Thus the valve elements material must be acid resistance. Teflon, which is used generally as inner parts of a valve, tends to easily sticks to sliding surface by thermal expansion under high temperature. Some studies are performed to change teflon to another material and shape to have a better fluidity under the condition. The analysis of the thermal expansion is conducted by commercial FEM software to improve the problems. Boundary conditions were temperature and load in this study. From the analysis, the thermal expansion of stainless steel is verified to be lower than that of teflon under high temperature. Thus coupled teflon/stainless steel-made valve is applied to assembly line without danger due to thermal expansion.

• 한국공작기계학회논문집
• /
• 제11권1호
• /
• pp.52-60
• /
• 2002

The purpose of this research is to study the vibration and acoustic pressure radiation from a thin isotropic flat plate stiffened by a rectangular array of beams, and excited by a time harmonic point force. These constructions on aircraft and ship structures are often subjected to fiequency dependent pressure fluctuations and forces. Forces from the these excitations induce structural vibrations in a wide range of fiequencies, which may cause such things as acoustic fatigue and internal cabin noise in the aircraft. It is thus important that the response characteristics and vibration modes of such periodic structures be horn. From this theoretical model, the sound pressure levels(SPL) in a semi-infinite fluid(water) bounded by the plate with the variation in the locations of an external time harmonic point farce on the plate can be calculated efficiently using three numerical tools such as the Gauss-jordan method the LU decomposition method md the IMSL numerical package.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2000년도 추계학술대회 논문집
• /
• pp.382-389
• /
• 2000

The purpose of present study is to investigate for reducing pressure fluctuations in tile case of installing tile air-shafts on the side wall of the tunnel with small cross-sectional area on conventional line. Experiments were performed with a 1/61-scale moving model rig for the tunnel of 0.764km length in the condition of tunnel cross-section area of 28 ㎡ According to the results, the maximum pressure fluctuation is reduced by 45% for 19 air-shafts. This results have the speed-up effects of about 33.4km/h for the train running in tunnel.

• 대한기계학회논문집B
• /
• 제20권11호
• /
• pp.3649-3654
• /
• 1996

A transient hydraulic flow rate computation scheme is described here so that the transient hydraulic flow rate can be determined using the dynamic pressure measurements at the ends of a straight flow line with a dynamic model of the hydraulic line. This method can be applied to determine the orifice ares of high response valve. Simulation results indicate that the method is relatively robust to realistic levels of uncertainties in the fluid properties.

• 한국안전학회지
• /
• 제16권1호
• /
• pp.25-30
• /
• 2001

This paper studies the effect of vibration characteristics of tube line conveying fluid with the power steering system of bus. We modelled fluid-filled tube line using I-DEAS software to investigate vibration characteristics of the power steering tube line. And we obtained the natural frequency of tube line through finite element analysis. Analytic solutions were compared with experimental solutions to verify finite element model. We tested the tube line to examine an effect of pressure pulse by vane pump and variation of geometry of tube. From both the experimental results and the modeling results for vibration characteristics of the tube line conveying fluid, we confirmed that vibration characteristics induced by pulse propagated along the power steering tube line and resonance occurred around the natural frequency with pulse excitation.

• 한국자동차공학회논문집
• /
• 제10권3호
• /
• pp.201-208
• /
• 2002

In this paper, the control strategy of ratio changing system for a metal belt CVT adopting primary pressure regulation is developed, and the shirting performance of pressure regulating type CVT with the suggested control strategy is investigated. The control strategy suggested in this study is composed of 2 feedback loop, one is speed ratio feedback and the other is primary pressure feedback. The pressure feedback is adopted to ensure prohibiting a belt slip during transient period in a fast downshift mode. Simulation results show that the system with suggested control strategy gives appropriate response time and tracking Performance for upshift and also gives a proper primary pressure which can prohibit the belt slip. In addition, it is fecund that the given system has an acceptable servo property in tracking the target speed ratio and robustness for the disturbance of line pressure.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.1655-1660
• /
• 2004

Theoretical study has been conducted to clarify pressure characteristics of KTX(Korea Train eXpress) in tunnel. The external and internal pressure of rolling stock have been measured by using the atmospheric pressure sensors and portable data acquisition system on Seoul-Busan high speed railroad line. These pressure change may give rise to the ear-discomfort for passenger and fatigue for car body. In this study, the tunnels from 200m to 4000m in length have been chosen for the investigation of tunnel length effects. From the results of experiment, the pattern of pressure change generally agrees to RTRI's experimental result for Shinkansen. We found that there are similar patterns of external pressure variation for each critical tunnel length. The critical tunnel lengths are governed by train speed, train length and sonic velocity.