scholarly journals The THE EFFECT OF HUMID TROPICAL CLIMATE ON FRICTION CHARACTERISTIC OF PNEUMATIC CYLINDERS

2021 ◽  
pp. 1-6
Author(s):  
Thuy Nguyen ◽  
Van Hung Pham
Keyword(s):  
Relative Humidity ◽  
Friction Force ◽  
Static Friction ◽  
Tropical Climate ◽  
Pneumatic Cylinder ◽  
Friction Characteristic ◽  
Humid Tropical Climate ◽  
Geographical Regions ◽  
Climatic Environment ◽  
Pneumatic Cylinders

The pneumatic cylinder is influenced by many various factors at work, including the climate environment. The climatic environment consists of two characteristic factors as temperature (T) and relative humidity (RH), which change according to seasons and different geographical regions. Therefore, changing the climate characteristic factors will affect the friction characteristic of pneumatic cylinders when operating at different speeds. This article presents empirical research on the simultaneous effects of temperature and relative humidity of the environment with the humid tropical climate in Vietnam on the pneumatic cylinder's friction properties. According to experimental planning, the studies were conducted on industrial pneumatic cylinders with two input factors: the temperature of 150C, 320C and 490C and relative humidity of 51%, 75% and 99%, with velocities of 30, 50 and 100 mm/s. The results show that the static friction force and dynamic friction decrease when T, RH increases, and the influence of air relative humidity on friction force is more significant than temperature. The experiment also gives an empirical regression equation on the relationship of friction in the pneumatic cylinder, depending on the two factors of temperature and relative humidity of the humid tropical climate in Vietnam with velocities of 30, 50 and 100 mm/s.

Study of the effects of relative humidity and velocity on the friction characteristics of pneumatic cylinders

2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040139
Author(s):  
Thuy-Duong Nguyen ◽  
Van-Hung Pham
Keyword(s):  
Relative Humidity ◽  
Sliding Friction ◽  
Static Friction ◽  
Pneumatic Cylinder ◽  
Dynamic Friction ◽  
Friction Forces ◽  
Measuring Device ◽  
Friction Characteristics ◽  
Rod Seals ◽  
Pneumatic Cylinders

The movement of a piston rod in a pneumatic cylinder is directly affected by the air humidity in the atmosphere, especially in the case of piston rods without any means of protection or grease on their surfaces. In a pneumatic cylinder system, the friction between the piston rod and the rod seal is sliding friction, and it has a significant value that varies with the variation in the moisture on the piston rod’s surface. In this paper, an investigation of the friction characteristics of piston rods and rod seals in a pneumatic cylinder was carried out with different humidity and velocity values to understand the effect of lubricants on the moving parts of pneumatic systems in humid environments, where the friction characteristics of the displacements corresponding to the static and dynamic friction forces were displayed on a measuring device. The research results showed that the static friction forces tended to decrease by [Formula: see text] and that the dynamic friction forces tended to decrease by [Formula: see text] when the relative humidity increased from 51% to 99% at different velocities between 5 and 100 mm/s.

Applying the Passivhaus standard to a terraced house in a hot and humid tropical climate – Evaluation of comfort and energy performance

2020 ◽  
Vol 41 (3) ◽  
pp. 247-260
Author(s):  
Roy Candra Sigalingging ◽  
David Chow ◽  
Steve Sharples
Keyword(s):  
Relative Humidity ◽  
Thermal Comfort ◽  
Air Conditioning ◽  
Best Practice ◽  
Natural Ventilation ◽  
Tropical Climate ◽  
Energy Performance ◽  
Tropical Region ◽  
Humid Tropical Climate ◽  
Air Temperatures

In a hot and humid tropical climate, natural ventilation brings high levels of moisture into dwellings that, together with occupant activity, can result in very elevated internal relative humidity levels. Coupling these high relative humidities with high internal air temperatures creates occupant thermal discomfort, which is typically ameliorated in the tropics using energy-intensive air conditioning systems. This paper has investigated the potential benefits for thermal comfort and energy usage of applying the German Passivhaus standard to tropical dwellings. By creating a super insulated and air-tight envelope, the Passivhaus standard reduces fabric heat transfer, controls air infiltration and provides low-energy comfort. Applying this approach to a tropical terraced house might be effective but could, potentially, have an adverse impact on mechanical cooling demand. This study took an actual terraced property in Jakarta, Indonesia and thermally modelled its performance as insulation and airtightness levels were incrementally improved up to the Passivhaus standard. Field measurements in the dwelling of air temperature and relative humidity were used to validate the thermal model of the existing house. The validated model then tested the feasibility of meeting the Passivhaus energy standard for cooling in the modified tropical house. Simulation allowed the effects of air conditioning (AC) and dehumidifiers on thermal comfort and cooling loads to be investigated. The research develop the Passivhaus building model that had the floor insulation removed to let the ground floor act as a thermal sink and potentially provide radiant cooling. Analysis revealed that the building’s predicted air temperatures were affected in a beneficial way by having the Passivhaus without floor insulation. Practical application: Cooling in hot and humid tropical region is an energy-intensive approach. Design approaches that can bring comfort and save energy for the occupant are essential. The success of Passivhaus standard in mild climate might be transferable to bring comfort in tropical housing. Best practice can be developed by analysing the Passivhaus building performance in hot and humid tropical region.

Influence of relative humidity and air temperature on the stopping position of the automatic tool changer in a CNC machine when using a pneumatic cylinder

2021 ◽  
pp. 2140013
Author(s):  
Hung Pham Van ◽  
Duong Nguyen Thuy
Keyword(s):  
Relative Humidity ◽  
Friction Force ◽  
Air Temperature ◽  
Numerical Control ◽  
Pneumatic Cylinder ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cnc Milling Machine ◽  
Automatic Tool Changer ◽  
Automatic Tool

The automatic tool changer (ATC) in computerized numerical control (CNC) milling machine often uses pneumatic dynamic sources. Friction in the pneumatic cylinder affects the ATC’s stopping position; this friction depends on many factors, including the air environment’s relative humidity and temperature. This paper presents the results of research on the effects of relative humidity (RH) and air temperature (T) on the stopping position of an ATC using a pneumatic cylinder. Studies were conducted at temperatures of [Formula: see text]C, [Formula: see text]C and [Formula: see text]C and relative humidity values of 51%, 75% and 99% for different speeds of the pneumatic cylinder (30, 50 and 100 mm/s). The results show that when the humidity increases from 51% to 99% and the temperature increases from [Formula: see text]C to [Formula: see text]C, the friction force decreases. The friction force is related to the relative humidity and temperature of the air. Thus, the deviation of the ATC’s stopping position depends on the relative humidity and temperature of the area under investigation.

New Pneumatic Cylinders for Improving Servo Actuator Positioning Accuracy

2004 ◽  
Vol 126 (4) ◽  
pp. 744-747 ◽  
Author(s):  
Igor L. Krivts
Keyword(s):  
Control System ◽  
Friction Force ◽  
Pneumatic Cylinder ◽  
Experimental Examination ◽  
Positioning Accuracy ◽  
Servo Actuator ◽  
And Control ◽  
Improved Accuracy ◽  
Accuracy Performance ◽  
Pneumatic Cylinders

Positioning accuracy of pneumatic servo actuators depends on parameters of the actuator and control system, and also on the friction force. This paper reports on new constructions of the pneumatic cylinders, which are the integral part of the servo actuator. Experimental examination of these servo actuators has shown that they could provide improved accuracy performance over the system with ordinary pneumatic cylinder.

scholarly journals Experimental investigation of friction behavior in pre-sliding regime for pneumatic cylinder

2014 ◽  
Vol 36 (4) ◽  
pp. 283-290
Author(s):  
Tran Xuan Bo ◽  
Pham Tat Thang ◽  
Do Thanh Cong ◽  
Ngo Sy Loc
Keyword(s):  
Friction Force ◽  
Friction Model ◽  
Operating Conditions ◽  
Experimental Results ◽  
Hysteretic Behavior ◽  
Pneumatic Cylinder ◽  
Experimental Investigations ◽  
Friction Behavior ◽  
Piston Displacement ◽  
Pneumatic Cylinders

Friction always presents in pneumatic cylinders and causes difficulties in controlling position and velocity of pneumatic systems. In order to improve the control performance of the pneumatic systems, it is necessary to fully understand behavior of friction in the pneumatic cylinders. So far, dynamic friction behavior of pneumatic cylinders has been investigated but mainly focused on the friction behavior in sliding regime. In pre-sliding regime, friction behavior has not been investigated. In this paper, experimental investigations of friction behavior of a pneumatic cylinder in pre-sliding regime are made. The friction force is calculated from the equation of motion of the piston using the measured values of pressures in the two cylinder chambers and the piston displacement. The pressures are controlled by using two proportional pressure control valve. The friction force versus piston displacement characteristics are measured and analysed under various operating conditions of the applied force and the pressures. Experimental results show that: i) the piston motion in pre-sliding regime exhibits a nonlinear spring behavior; ii) hysteretic behavior with nonlocal memory is verified; iii) the pressures have influence only on the size of the hysteretic loop. These experimental results can be applied to develop a friction model for pneumatic cylinders.

Optimization of the Cross Section of an Elastomeric Seal for Pneumatic Cylinders

2005 ◽  
Vol 128 (2) ◽  
pp. 406-413 ◽  
Author(s):  
Guido Belforte ◽  
Andrea Manuello ◽  
Luigi Mazza
Keyword(s):  
Finite Element ◽  
Friction Force ◽  
Cross Section ◽  
Test Bench ◽  
Frictional Contact ◽  
Pneumatic Cylinder ◽  
The Cross ◽  
Cylinder Bore ◽  
Pneumatic Cylinders ◽  
Elastomer Seal

The cross section of an elastomer seal for pneumatic actuator pistons was optimized to minimize the friction force exchanged with the cylinder bore. The new seal geometry was developed using a finite element numerical model which takes material nonlinearities and frictional contact with seat and cylinder bore surfaces into account. The friction force exchanged between the new seal and the pneumatic cylinder bore was measured experimentally using a suitable sensorized test bench.

scholarly journals The Evaluation of the environmental parameters of battery-caged poultry house in the humid tropical climate

2020 ◽  
pp. e753
Author(s):  
Ayoola Olawole Jongbo
Keyword(s):  
Heat Stress ◽  
Relative Humidity ◽  
Environmental Parameters ◽  
Tropical Climate ◽  
Stress Index ◽  
Air Velocity ◽  
Humid Tropical Climate ◽  
Airflow Distribution ◽  
Hot Weather ◽  
Heat Stress Index

Heat stress is a key factor affecting the productions of the animals. In laying birds, it could cause loss of body weight and high mortality. To this end, a study was carried out in a naturally ventilated, tier-caged layer house to evaluate the environmental parameters and the heat stress index within the building during hot weather period. Throughout the study, the environmental parameters (air temperature, relative humidity and air velocity), inside and outside the experimental building were measured and recorded. The heat stress index using the temperature-humidity index (THI) was also estimated. The results of the study indicated that laying birds in this study were most of their lifetime subjected to hot conditions which could have a significant effect on their performances. It was also found out that the air velocity within the building was very low (0.07 ms-1 to 0.58 ms1) which could not provide a cool environment for the birds. The heat stress index (THI) inside laying bird building was found to be mostly influenced by high relative humidity compared to ambient temperature. Therefore, it would be appropriate if the airflow distribution inside the poultry building, in this study, could be evaluated using computational fluid dynamics to understand the velocity profile within the building. This could assist engineers to redesign the building and make it appropriate for laying birds in the humid tropical climate.

Water Budget of Constructed Wetland System with Subsurface Vertical Flow in Sub-Humid Tropical Climate

2015 ◽  
Vol 1 (5) ◽  
pp. 235-242
Author(s):  
Édio Damásio da Silva Júnior ◽  
Rogério de Araújo Almeida ◽  
Elisa Rodrigues Siqueira ◽  
Ábio Roduvalho da Silva
Keyword(s):  
Constructed Wetland ◽  
Water Budget ◽  
Tropical Climate ◽  
Vertical Flow ◽  
Humid Tropical Climate ◽  
Wetland System

Experimental Study of Static Friction in a Spherical Elastic-Plastic Contact

2008 ◽  
Author(s):  
Andrey Ovcharenko ◽  
Gregory Halperin ◽  
Izhak Etsion
Keyword(s):  
Friction Force ◽  
Normal Load ◽  
Static Friction ◽  
Tangential Displacement ◽  
Accurate Identification ◽  
Elastic Plastic ◽  
Static Friction Coefficient ◽  
Wide Range ◽  
Material Good ◽  
Contact Diameter

The elastic-plastic contact between a deformable sphere and a rigid flat during pre-sliding is studied experimentally. Measurements of friction force and contact area are done in real time along with an accurate identification of the instant of sliding inception. The static friction force and relative tangential displacement are investigated over a wide range of normal preloads for several sphere materials and diameters. It is found that at low normal loads the static friction coefficient depends on the normal load in breach of the classical laws of friction. The pre-sliding displacement is found to be less than 5 percent of the contact diameter, and the interface mean shear stress at sliding inception is found to be slightly below the shear strength of the sphere material. Good correlation is found between the present experimental results and a recent theoretical model in the elastic-plastic regime of deformation.

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