A Statistical Analysis of Elastomeric Seal Degradation in a Pneumatic Cylinder With Variation of Temperature

2011 ◽  
Author(s):  
B. S. Kang ◽  
J. H. Shin ◽  
H. E. Kim
Keyword(s):  
Sliding Friction ◽  
Degradation Mechanism ◽  
Operating Parameter ◽  
Maintenance Cost ◽  
Pneumatic Cylinder ◽  
Analysis Method ◽  
Pyrolysis Gas ◽  
Life Tests ◽  
Stress Minimization ◽  
Pneumatic Cylinders

Pneumatic Cylinders are one of major mechanical components which are widely used in various industries such as automobile production line and semiconductor inspection device due to its low contamination and low maintenance cost. Most of existing studies on pneumatic cylinders have focused on their performance improvement such as operating sliding friction measurement, contact stress minimization, appropriate dynamic response, and etc. This research carried out life tests of pneumatic cylinders and the concerned failure mechanism was the degradation of pneumatic polyurethane seal since leakage caused by seal degradation occurs very frequently. The considered operating parameter was environmental temperature. To assess operating temperature as an acceleration parameter, the lifetime of a pneumatic cylinder was tested at high temperature and the degradation mechanism and characteristics of sealing surface were analyzed by statistical Weibull analysis method as well as by surface analysis using pyrolysis gas chromatography. Ultimately this research will help the life prediction of other pneumatic reciprocating machines.

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.

scholarly journals Prediction Methods for Routine Maintenance Costs of a Reinforced Concrete Beam Bridge Based on Panel Data

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaoli Shi ◽  
Bingbing Zhao ◽  
Yuling Yao ◽  
Feng Wang
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Concrete Beam ◽  
Reinforced Concrete Beam ◽  
Maintenance Cost ◽  
Analysis Method ◽  
Series Analysis ◽  
The Cost ◽  
Beam Bridge ◽  
Physical Engineering

In order to make informed decisions on routine maintenance of bridges of expressways, the hierarchical regression analysis method was used to quantify factors influencing routine maintenance cost. Two calculation models for routine maintenance cost based on linear regression and time-series analysis were proposed. The results indicate that the logarithm of the historical routine maintenance cost is the dependent variable and the bridge age is the independent variable. The linear regression analysis was used to obtain a cost prediction model for routine maintenance of a beam bridge, which was combined with the quantity and price, and verified by a physical engineering example. In order to cope with the cost changes and future demands brought about by the emergence of new maintenance technologies, the time-series analysis method was used to obtain a model to predict the engineering quantities for the routine maintenance of a bridge based on standardized minor repair engineering quantities. Taking into account the actual cost of the minor repair project as well as the time-series analysis’ sample size demands, the annual engineering quantity was randomly decomposed into four quarterly data quantities, and the time-series analysis result was verified by physical engineering. These results can improve the calculation accuracy of the routine maintenance costs of reinforced concrete beam bridges. Furthermore, it can have a certain application value for improving the cost measurement module of bridge maintenance management systems.

INFLUENCE OF NANOFILLER ON THERMAL DEGRADATION RESISTANCE OF HYDROGENATED NITRILE BUTADIENE RUBBER

2018 ◽  
Vol 92 (2) ◽  
pp. 263-285 ◽  
Author(s):  
Tuhin Saha ◽  
Anil K. Bhowmick
Keyword(s):  
Atomistic Simulation ◽  
Model Compound ◽  
Degradation Mechanism ◽  
Decomposition Temperature ◽  
Industrial Applications ◽  
Gas Chromatography Mass Spectrometry ◽  
Butadiene Rubber ◽  
Pyrolysis Gas ◽  
Initial Decomposition Temperature ◽  
Acrylonitrile Butadiene Rubber

ABSTRACT Studies on the degradation of elastomers and their prevention have become increasingly important in recent years because of stringent environmental conditions in many industrial applications. The reactive atomistic simulation was executed on a hydrogenated acrylonitrile-butadiene rubber (HNBR40) model compound composed of 40 monomer units. The reactive simulation was used to study the decomposition behavior of HNBR40, to visualize different pyrolysis products, and also to analyze the degradation mechanism of HNBR40. Ethylene, propylene, and acrylonitrile were observed as dominant products at lower temperature, and 1-butene was found at higher temperature. Pyrolysis–gas chromatography–mass spectrometry was used to verify the decomposition products obtained from the prediction of atomistic simulation. In this study, nanofillers, especially nanoclays and nanosilicas, were used to prevent degradation significantly. Restricted degradation by the nanofiller-reinforced rubber prolonged the durability. Furthermore, the reactive simulation was performed to understand thermal decomposition characteristics of the model compound in the presence of the nanofiller. The initial decomposition temperature, the final degradation temperature, and the rate of degradation improved to a great extent on the addition of the model nanosilica compound as obtained from the simulation studies. Moreover, the lifetime of nanoclay- and nanosilica-reinforced hydrogenated acrylonitrile–butadiene rubber was calculated by using thermogravimetric analysis, and its useful lifetime was compared with that of the pristine polymer in the application temperature range of 150 °C.

Photocatalytic Degradation of 2,4,5–TCP in TiO2/UV/H2O2 System

2012 ◽  
Vol 518-523 ◽  
pp. 2649-2652
Author(s):  
Yan Ping Zong ◽  
Xian Hua Liu ◽  
Xi Wen Du ◽  
Yi Ren Lu ◽  
Xiao Xuan Shi
Keyword(s):  
Hydrogen Peroxide ◽  
Photocatalytic Degradation ◽  
Absorption Spectroscopy ◽  
Degradation Mechanism ◽  
Analysis Method ◽  
Photocatalytic System ◽  
Initial Ph ◽  
Effects Of Ph

The photocatalytic degradation of 2,4,5–Trichlorophenol(2,4,5–TCP) in TiO2/UV/ H2O2 photocatalytic system was examined using absorption spectroscopy and GC-MS. It was found that 2,4,5–TCP could be degraded almost completely within 100 min under the conditions of initial pH 3, C(H2O2) = 0.08 mol/L and C(TiO2) = 0.5 g/L. The effects of pH and the concentration of hydrogen peroxide on the degradation of 2,4,5–TCP were also studied. Besides, the degradation mechanism was concluded accorrding to convertional analysis method too.

Study on Friction Characteristics of Energizing Pneumatic Cylinders

2014 ◽  
Vol 904 ◽  
pp. 306-310 ◽  
Author(s):  
Yan Jia Zhan ◽  
Tao Wang ◽  
Bo Wang
Keyword(s):  
Special Kind ◽  
Friction Model ◽  
Pneumatic Cylinder ◽  
Working Pressure ◽  
Friction Characteristics ◽  
Factors Affecting ◽  
Output Force ◽  
Experimental Apparatus ◽  
Depth Study ◽  
Pneumatic Cylinders

As a special kind of pneumatic cylinder, energizing pneumatic cylinder can increase the output force without changing diameter by a series of two or more piston on a piston rod. Since the friction characteristics of pneumatic cylinders is one of the most important factors affecting the nonlinearity, a new experimental apparatus is designed to have an in-depth study, base on exhaust throttle. The friction of energizing pneumatic cylinder was tested under different working pressure and velocity to ascertain the parameters of stribeck model. The results show that friction model of the energizing pneumatic cylinder can be the superposition of the models of each piston.

Detecting pneumatic actuator leakage using acoustic emission monitoring

2020 ◽  
Vol 62 (1) ◽  
pp. 22-26
Author(s):  
H Mahmoud ◽  
P Mazal ◽  
F Vlašic
Keyword(s):  
Acoustic Emission ◽  
Root Mean Square ◽  
Diagnostic Procedure ◽  
Pneumatic Cylinder ◽  
Mean Square ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Maximum Root ◽  
The Difference ◽  
Pneumatic Cylinders

This paper focuses on the development of an efficient new diagnostic procedure for checking the function of pneumatic cylinders using acoustic emission. This diagnostic procedure is able to detect distinctive differences that determine whether the cylinder is damaged or undamaged. Moreover, the paper aims to find the diagnostic criteria that can be used to evaluate the pneumatic cylinder and detect defects. In this study, acoustic emission testing of several undamaged cylinders is carried out before artificial defects are created in each one. The signals from the progress and retreat strokes are recorded and analysed according to many parameters. The root mean square is normalised and the different responses of damaged and undamaged pneumatic cylinders are recognised by the time delay of the strokes. The differences are identified by comparing the maximum root mean square from sensor A and the maximum root mean square from sensor B for one cycle in the retreat stroke. The damaged and undamaged cylinders are distinguished using the difference in energy values present in the signals of the two sensors in the retreat stroke. The final evaluation of the cylinder is determined by calculating the total value of the root mean square. This paper is a continuation of a prior article and the extension of that work.

Pneumatic cylinder with magnetorheological brake using serpentine and helix flux guide as a linear hybrid actuator for haptics

2016 ◽  
Vol 28 (10) ◽  
pp. 1303-1321 ◽  
Author(s):  
Max Cinq-Mars ◽  
Hakan Gurocak
Keyword(s):  
Power Efficiency ◽  
Position Control ◽  
Weight Ratio ◽  
Compressed Air ◽  
Pneumatic Cylinder ◽  
Shear Mode ◽  
Precise Position ◽  
Hybrid Actuator ◽  
Pneumatic Cylinders ◽  
Magnetorheological Brakes

This research explored a new linear hybrid actuator, which consists of a pneumatic cylinder with a magnetorheological brake embedded in its piston. Magnetorheological brakes are promising actuators since they can apply large forces in a small actuator size, but they can only oppose motion, as they are passive actuators. Pneumatic cylinders are desirable actuators due to their high force-to-weight ratio and ability to apply active forces. However, they require expensive servo valves for precise position control. The new hybrid actuator benefits from the advantages of magnetorheological brakes and pneumatic cylinders. It can apply forces using compressed air and can resist external forces using the magnetorheological brake. The embedded brake also eliminates the undesirable side effects of using compressed air and allows precise positioning of the piston anywhere in its stroke with simple solenoid valves. Fields such as haptics and robotics might benefit greatly from the use of the hybrid actuator where a high force-to-weight ratio could be employed. The study contributes (1) a triple helix flux guide for the linear magnetorheological brake, (2) serpentine flux path to enable larger braking forces, (3) shear mode activation, and (4) control algorithms that enable use of simple solenoid valves and improved power efficiency. When compared to an existing purely pneumatic control algorithm, the hybrid actuator exceeded the performance in position tracking and force disturbance rejection. A power management algorithm demonstrated that disabling the brake when the piston was in position vastly decreases the power consumption.

A Novel Deployable Hexahedron Mobile Mechanism Constructed by Only Prismatic Joints

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Wan Ding ◽  
Yan-an Yao
Keyword(s):  
Control Strategy ◽  
Stable State ◽  
Necessary Condition ◽  
Pneumatic Cylinder ◽  
Symmetrical Structure ◽  
System A ◽  
Prismatic Joints ◽  
Binary Control ◽  
The Stability ◽  
Pneumatic Cylinders

This paper proposes a novel deployable hexahedron mobile mechanism that is rigidly linked by only prismatic joints. The mechanism that is a completely symmetrical structure can always keep the walking capability when any of its six faces of the hexahedron touches the ground. It can roll at any stable state. The configuration constructed by only prismatic joints makes it expand and contract as a deployable structure. In this paper, a method for constructing a deployable hexahedron mobile mechanism is proposed. The stability analysis and dynamic simulation of the walking and rolling are carried out. The necessary condition of tipping motion and the speed analysis of two different rolling gaits are studied in details. A binary control strategy is adopted to simplify the complexity of the control system. A pneumatic cylinder is chosen to be the binary actuator. A prototype composed of 180 pneumatic cylinders was fabricated. The validity of the walking and tipping functions are verified by the experimental results.

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