Theoretical, simulation and experimental investigation of 1D hybrid pressure distribution for internal gear motors and pumps

Trong Hoa Pham,Dinh Tu Nguyen,Jürgen Weber 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1

Internal gear motor and pump is the typical rotating machine which operates in hybrid regime of lubrication. Calculation of the pressure distribution in the oil-lubrication film is the fundamental issue for determination of the upper and lower speed limit as well as analysis of the stability phenomenon of internal gear motor and pump. However, the simultaneously existence problem of hydrodynamic and hydrostatic pressure in case of hybrid regime is a challenge for calculation. This paper introduces an approach for calculation of 1D hybrid pressure distribution. The Reynolds equation with appropriate boundary condition is solved to obtain 2D hydrodynamic pressure distribution by using the finite difference method (FDM). The resistance network model (RNM) is used to predict the 1D hydrostatic pressure profile. Based on the hydrostatic and hydrodynamic pressure, the 1D total pressure profile can be retrieved. The CFD simulation has been performed to obtain the hydrostatic pressure profile and then compare to the hydrostatic pressure distribution by using RNM. A test rig has been designed to measure the oil-film pressure at five different points over the circumferential direction. Results pointed out that the numerical calculation agree well with the experimental results, particularly at high values of the working pressure.

고층 주거건물에서의 압력분포 예측을 통한 압력차 문제 평가

조재훈 대한건축학회 2005 대한건축학회논문집 Vol.21 No.11

It is very important to estimate the stack pressure difference across exterior walls for understanding the energy impacts of infiltration and ventilation in high-rise buildings, because stack pressure is likely to significantly affect energy load and is sustained over a long period. This paper proposes a simple evaluation criteria for investigating the pressure difference problems and prediction process for estimating the pressure distribution in high-rise residential buildings, using key parameters that affect the magnitude and distribution of stack pressure. First, the stack pressure is predicted from parameters such as the height of the elevator shaft, the location of the neutral pressure level for each shaft, and the interior temperature of each shaft. Then, the pressure distribution of each floor is calculated using the equivalent leakage areas of the exterior and interior walls.

Gait / Foot Pressure Measurement Techniques - Development of Low-Cost Measurement Method

( D. Mounika ),( N. Arun ),( Seung Nam Min ),( Murali Subramaniyam ) 한국감성과학회 2021 추계학술대회 Vol.2021 No.0

Purpose: The geometrical balance or equilibrium of the human body’s musculoskeletal system are represented by foot pressure distribution. Improper Foot Pressure Distribution leads to multiple disorders like lower back pain, leg pain, and mild pronation, which further impacts body balance. The objective of the proposed work is two-fold (i) To understand the techniques available for measuring foot interface pressure and (ii) To develop a low cost and portable measuring technique in both static and dynamic conditions for specific applications. Methods: Multiple literatures from various databases with combination of keywords like foot pressure distribution, force sensor, wearable insole, force plate and gait pattern from past ten years are examined. Results: The literature was reviewed and a comparative study has been conducted to produce the pros and cons of each measuring technique. Also, the correlation between foot pressure distribution and key factors like gender, age, height and weight were analyzed to understand the body balance and gait pattern. To propose a low cost and portable foot pressure measuring technique. Conclusion: Validate the proposed techniques with available standard method. Effects of improper foot pressure distribution are examined and the techniques to measure improper foot pressure distribution are compared.

Gait / Foot Pressure Measurement Techniques - Development of Low-Cost Measurement Method

( D. Mounika ),( N. Arun ),( Seung Nam Min ),( Murali Subramaniyam ) 한국감성과학회 2021 한국감성과학회 국제학술대회(ICES) Vol.2021 No.-

Purpose: The geometrical balance or equilibrium of the human body’s musculoskeletal system are represented by foot pressure distribution. Improper Foot Pressure Distribution leads to multiple disorders like lower back pain, leg pain, and mild pronation, which further impacts body balance. The objective of the proposed work is two-fold (i) To understand the techniques available for measuring foot interface pressure and (ii) To develop a low cost and portable measuring technique in both static and dynamic conditions for specific applications. Methods: Multiple literatures from various databases with combination of keywords like foot pressure distribution, force sensor, wearable insole, force plate and gait pattern from past ten years are examined. Results: The literature was reviewed and a comparative study has been conducted to produce the pros and cons of each measuring technique. Also, the correlation between foot pressure distribution and key factors like gender, age, height and weight were analyzed to understand the body balance and gait pattern. To propose a low cost and portable foot pressure measuring technique. Conclusion: Validate the proposed techniques with available standard method. Effects of improper foot pressure distribution are examined and the techniques to measure improper foot pressure distribution are compared.

Simplified Prediction Method of Stack-Induced Pressure Distribution in High-rise Residential Buildings

Jo, Jae-Hun,Seok, Ho-Tae,Yeo, Myoung-Souk,Kim, Kwang-Woo Architectural Institute of Japan 2009 JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEE Vol.8 No.1

<P>This paper presents a simple prediction strategy for estimating the pressure distribution in high-rise residential buildings, using key parameters that affect the magnitude and distribution of stack pressure. The strategy is composed of two procedures: first, the stack pressure is predicted from parameters such as the height of the elevator shaft, the location of the neutral pressure level for each shaft, and the interior temperature of each shaft. Then, the pressure distribution of each floor is calculated using the equivalent leakage areas of the exterior and interior walls, by which finally the pressure difference across the exterior walls can be estimated. To verify the feasibility of this strategy, the predicted pressure differences across exterior walls were compared to measured data of a high-rise residential building with multiple elevator zoning. The results show that this strategy can predict pressure distribution quickly with satisfactory results for both the architectural designer and HVAC engineer.</P>

기능성 전문테니스화의 족저압력분포 분석

이중숙,김용재,박승범 한국운동역학회 2004 한국운동역학회지 Vol.14 No.3

J. S. LEE, Y. J. KIM, S. B. PARK. A Study of In-sole Plantar Pressure Distribution in Functional Tennis Shoes. Korean Journal of Sport Biomechanics, Vol. 14, No. 3, pp. 99-118, 2004. The aim of this study is to evaluate tennis shoes's plantar pressure distribution in tennis prayers and to determine the influence of the shoe on various tennis movements. When investigating the biomechanics of movement in tennis, one of the first things to do is to understand the movement patterns of the sport, specifically how these patterns relate to different tennis shoes. Once these patterns are understood, footwear company can design tennis shoes that match the individual needs of tennis players. Plantar pressure measurement is widely employed to study foot function, the mechanical pathogenesis for foot disease and as a diagnostic and outcome measurement tool for many performance. Measurements were taken of plantar pressure distribution across the foot and using F-Scan(Tekscan Inc.) systems respectively. The F-Scan system for dynamic in-shoe foot pressure measurements has enabled us to assess quantitatively the efficacy of different types of footwear in reducing foot pressures. The Tekscan F-Scan system consists of a flexible, 0.18mm thick sole-shape having 1260 pressure sensors, the sensor insole was trimmed to fit the subjects' right, left shoes. For this study 4 university male, high level tennis players were instructed to hit alternated forehand stroke, backhand stroke, forehand volley, backhand volley, smash, service movement in 4 different tennis shoes. 1. When impact in tennis movement, peak pressure distribution of landing foot displayed D>C>B>A, A displayed the best low pressure distribution. A style's tennis shoes will suggest prayer with high impact. If prayer with high impact feeling during pray in tennis wear A style, it will decrease injury, will have performance improvement. 2. When impact in tennis movement, plantar pattern of pressure distribution in landing foot displayed B>A>C>D in stability performance. During tennis, prayer want to stability movement suggest B style tennis shoes when tennis movement impact keep stability of human body. B style tennis shoes give performance improvement 3. When impact in tennis movement, plantar pattern of center of force(C.O.F.)trajectory in landing foot analyzed this : 1) When stroke movement and volley movement in tennis, prayer better to rearfoot movement. 2) when service movement, prayer midfoot strike movement. 3) when smash movement, prayer have forefoot strike movement.

균일 가압을 적용한 Wafer Polishing 가공 성능에 관한 연구

원종구(J.K Won),이정택(J.T Lee),이은상(E.S Lee) 한국생산제조학회 2006 한국공작기계학회 춘계학술대회논문집 Vol.2006 No.-

Wafer polishing makes the surface planarization to achieve a high-quality. The pressure distribution is an important parameter of polishing process. This study shows the pressure distribution between the polishing pad and the wafer attached by machine's head. The experiments were performed to observe the morphology of pressure, when the machine's head was pressed down onto the polishing pad. It is found that the pressure distribution is depended on the damping materials in the preliminary experiment. To measure the pressure distribution, the pressure measuring film is used. The simulation result of head is compared with the measured pressure distribution. As the static pressures are compared, it will be shown the status of pressure by the damping materials of machine's head. On polishing experiment, vibration and frequency were measured and analyzed.

균일 가압을 적용한 Wafer Polishing 가공 성능에 관한 연구

원종구(J.K Won),이정택(J.T Lee),이은상(E.S Lee) 한국생산제조학회 2006 한국생산제조시스템학회 학술발표대회 논문집 Vol.2006 No.5

Wafer polishing makes the surface planarization to achieve a high-quality. The pressure distribution is an important parameter of polishing process. This study shows the pressure distribution between the polishing pad and the wafer attached by machine's head. The experiments were performed to observe the morphology of pressure, when the machine's head was pressed down onto the polishing pad. It is found that the pressure distribution is depended on the damping materials in the preliminary experiment. To measure the pressure distribution, the pressure measuring film is used. The simulation result of head is compared with the measured pressure distribution. As the static pressures are compared, it will be shown the status of pressure by the damping materials of machine's head. On polishing experiment, vibration and frequency were measured and analyzed.

균일 가압을 적용한 Wafer Polishing 가공 성능에 관한 연구

원종구,이정택,이은상 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

Wafer polishing makes the surface planarization to achieve a high-quality. The pressure distribution is an important parameter of polishing process. This study shows the pressure distribution between the polishing pad and the wafer attached by machine's head. The experiments were performed to observe the morphology of pressure, when the machine's head was pressed down onto the polishing pad. It is found that the pressure distribution is depended on the damping materials in the preliminary experiment. To measure the pressure distribution, the pressure measuring film is used. The simulation result of head is compared with the measured pressure distribution. As the static pressures are compared, it will be shown the status of pressure by the damping materials of machine's head. On polishing experiment, vibration and frequency were measured and analyzed.

A Study on Pressure Distribution for Uniform Polishing of Sapphire Substrate

Park, Chul jin,Jeong, Haedo,Lee, Sangjik,Kim, Doyeon,Kim, Hyoungjae Korean Tribology Society 2016 한국윤활학회지(윤활학회지) Vol.10 No.2

Total thickness variation (TTV), BOW, and surface roughness are essential characteristics for high quality sapphire substrates. Many researchers have attempted to increase removal rate by controlling the key process parameters like pressure and velocity owing to the high cost of consumables in sapphire chemical mechanical polishing (CMP). In case of the pressure approach, increased pressure owing to higher deviation of pressure over the wafer leads to significant degradation of the TTV. In this study, the authors focused on reducing TTV under the high-pressure conditions. When the production equipment polishes multiple wafers attached on a carrier, higher loads seem to be concentrated around the leading edge of the head; this occurs because of frictional force generated by the combination of table rotation and the height of the gimbal of the polishing head. We believe the skewed pressure distribution during polishing to be the main reason of within-wafer non-uniformity (WIWNU). The insertion of a hub ring between the polishing head and substrate carrier helped reduce the pressure deviation. Adjusting the location of the hub ring enables tuning of the pressure distribution. The results indicated that the position of the hub ring strongly affected the removal profile, which confirmed that the position of the hub ring changes the pressure distribution. Furthermore, we analyzed the deformation of the head via finite element method (FEM) to verify the pressure non-uniformity over the contact area Based on experiment and FEM results, we determined the optimal position of hub ring for achieving uniform polishing of the substrate.