Simulating Tire Inflation Pressure Loss Rate Test by the Ideal Material Method

2019 ◽  
Vol 20 (4) ◽  
pp. 789-800
Author(s):  
Chen Liang ◽  
Xinyu Zhu ◽  
Changda Li ◽  
Guolin Wang ◽  
Liu Ji
2011 ◽  
Vol 39 (2) ◽  
pp. 125-160 ◽  
Author(s):  
John Daws

Abstract Nitrogen as an inflation gas for passenger car and light truck tires use is widely available commercially. Consumers are confronted with a bewildering selection of offerings, and suppliers tout the purity of their nitrogen generation systems and effectiveness of using the gas in place of air. This paper develops models for the initial tire nitrogen purity, the inflation pressure loss rate, and the evolution of the nitrogen gas purity in the tire as a function of the gas used to top off the tire over its life. A series of simulations using the basic model is developed for air and various purities of nitrogen initial inflation with monthly top-off using air or various purities of nitrogen. The initial inflation pressure loss rate is shown as a function of the tire’s initial nitrogen purity. This paper proposes the use of the total oxygen passing through the tire over its lifetime as a metric for evaluation of various inflation schemes. This metric is developed for several of the popular available nitrogen inflation purities using both air and nitrogen as a top-off gas.


2015 ◽  
Vol 43 (4) ◽  
pp. 325-337 ◽  
Author(s):  
Jonathan E. Martens ◽  
Edward R. Terrill ◽  
R. Christopher Napier ◽  
Walter H. Waddell

ABSTRACT The inflation pressure loss rate (IPLR) of a tire has been a standard test method for several decades and is used to determine the rate at which a tire will lose pressure. Following these procedures, the rate of pressure loss is obtained and expressed numerically as the percentage of loss per month. This is an investigation of two experimental variables: (1) the frequency at which the inflation pressure is measured on a daily basis, and (2) the duration of the entire test. The measurement frequency means how many data points are recorded during a 24-hour period. For example, one study may collect data as infrequently as once per day by manually reading a pressure gauge every 24 hours. Alternatively, another study may collect data electronically with pressure transducers capable of transmitting large numbers of data points over short preset periods, then numerically averaging those data into a single 24-hour daily measurement. After a 21-day period to equilibrate the newly inflated tire, the test duration can range from 90 to 180 days but is allowed to be shortened when using electronic-pressure monitoring. This is a study of data-collection frequency and duration in a newly commissioned tire IPLR laboratory at Akron Rubber Development Laboratory, Inc (ARDL). It was constructed to have excellent temperature control and was equipped with 24 pressure-sensitive transducers with data being directly transmitted into a dedicated computer where the ASTM F1112 equations were applied. The present study includes data measurements from 56 radial medium truck tires manufactured by different companies. Results were obtained by averaging data collected four times per hour over a test duration of 90 days but were then recalculated using 60, 45, or 30 days of data to establish the feasibility of using a shorter testing time.


1979 ◽  
Vol 52 (5) ◽  
pp. 905-919 ◽  
Author(s):  
D. M. Coddington

Abstract Maintaining proper inflation pressure in tubeless tires, particularly radials, is critical to maximum tread wear life, durability, and minimum rolling resistance for vehicle fuel economy. This paper has discussed experimental studies of tubeless tire inflation pressure loss and how it is affected by tire size, operating pressure and temperature, and innerliner construction. Inflation pressure loss rates have been measured for varied commercial production tire constructions and sizes under static, constant temperature conditions. Pilot plant built radial passenger tires with varied innerliners have been tested for inflation loss rate, both statically and dynamically. A model equation has been developed to relate inflation pressure retention (IPR) to principal parameters of tire geometry, service and innerliner construction. Correlation of predicted air retention with actual performance is promising. A tire immersion test procedure has been employed to demonstrate air loss via migration and to study its paths. These studies indicate that properly fitted tubeless tires, free of mechanical leaks, can still have significant pressure loss via permeation; that the rate of loss increases as tire size is reduced; and that an ultra-low permeability innerliner can greatly improve tire inflation retention under static and dynamic service conditions.


1992 ◽  
Vol 20 (4) ◽  
pp. 200-211 ◽  
Author(s):  
B. Costemalle

Abstract The inflation pressure loss and carcass pressure build-up (intracarcass pressure or ICP) of tubeless tires can be predicted with a simple theoretical model. Tire construction and relative air permeabilities of the main tire components are significant factors in the pressure loss and ICP. Highly impermeable liners play a major role in obtaining optimum results. Application of the model to recent European passenger tire surveys is shown.


2004 ◽  
Vol 61 (12) ◽  
pp. 2339-2349 ◽  
Author(s):  
Isabelle L Girard ◽  
James W.A Grant ◽  
Stefán Ó Steingrímsson

The ideal despotic distribution predicts that individuals occupying preferred habitats will have higher fitness than those in less preferred habitats, whereas the ideal free distribution predicts that average fitness will be equal in all habitats. To test between these two alternatives, we studied habitat use in relation to foraging, growth, and loss rates of 216 individually tagged young-of-the-year Atlantic salmon (Salmo salar). Fish were observed by snorkelling between 2 July and 4 September 1999 in Catamaran Brook, New Brunswick. In a multiple logistic regression, the variables that best discriminated between the habitats used and not used by fish were mean flow velocity and water depth; the fish preferred habitats of intermediate flow velocity (6–48 cm·s–1) and depth (20–39 cm). Fish in preferred habitats experienced higher levels of food abundance and had higher foraging rates but did not differ in body size or growth rate compared with those in less preferred habitats, perhaps because of higher energetic costs. In addition, loss rate did not differ significantly between preferred and less preferred habitats. Our data suggest that salmonid populations at low density may be better described by an ideal free distribution rather than by an ideal despotic one.


2015 ◽  
Vol 107 ◽  
pp. 123-130 ◽  
Author(s):  
Dong-Seok Lee ◽  
Seung-Jin Kim ◽  
Young-Hum Cho ◽  
Jae-Hun Jo

2019 ◽  
Vol 48 (4) ◽  
pp. 329-353
Author(s):  
Chen Liang ◽  
Xinyu Zhu ◽  
Guolin Wang ◽  
Changda Li

ABSTRACT Tire inflation pressure loss is inevitable during tire service time. The inflation pressure loss rate (IPLR) is widely used to estimate the inflation pressure retention performance of a tire. However, an IPLR test is a time-consuming process that lasts 42 days for a passenger car tire and 105 days for a truck/bus tire. To perform a thorough study of the tire pressure loss process, based on Abaqus software, a finite element model was developed with tire geometry inputs as well as tire material inputs of both mechanical and permeability properties of the various rubber compounds. A new method—the ideal material method—is proposed here to describe the transient tire pressure loss. Different from the previous isotropic models, the cord–rubber system is described using orthotropic diffusivities, which were determined through air-pressure-drop tests then applied in the finite element model in this article. Compared with the standard IPLR test, the difference between the tire IPLR test and the simulation result is within 5%.


Author(s):  
James C. Paul ◽  
David R. Noles

Abstract A numerical procedure has been developed for the design of duct elbows that exhibit minimum pressure loss. A two-dimensional potential flow modeling method is used to determine the ideal static pressure distribution for a given elbow geometry. A turbulent boundary layer separation criterion is then used to determine whether the ideal distribution can be obtained. Those elbow designs for which flow does not separate are shown to produce minimum pressure loss. The procedure is also shown to be effective in the design of turning vanes. The design method is confirmed by experiments with a 90 degree elbow within a square duct.


Author(s):  
M.S. Shahrabadi ◽  
T. Yamamoto

The technique of labeling of macromolecules with ferritin conjugated antibody has been successfully used for extracellular antigen by means of staining the specimen with conjugate prior to fixation and embedding. However, the ideal method to determine the location of intracellular antigen would be to do the antigen-antibody reaction in thin sections. This technique contains inherent problems such as the destruction of antigenic determinants during fixation or embedding and the non-specific attachment of conjugate to the embedding media. Certain embedding media such as polyampholytes (2) or cross-linked bovine serum albumin (3) have been introduced to overcome some of these problems.


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