Effect of Measurement Frequency and Test Duration on the Inflation Pressure Loss Rate of Radial Medium Truck Tires

2015 ◽  
Vol 43 (4) ◽  
pp. 325-337 ◽  
Author(s):  
Jonathan E. Martens ◽  
Edward R. Terrill ◽  
R. Christopher Napier ◽  
Walter H. Waddell
Keyword(s):  
Pressure Loss ◽  
Loss Rate ◽  
Pressure Gauge ◽  
Test Method ◽  
Test Duration ◽  
Testing Time ◽  
Inflation Pressure ◽  
Measurement Frequency ◽  
Truck Tires ◽  
Data Points

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.

Nitrogen Inflation for Passenger Car and Light Truck Tires

2011 ◽  
Vol 39 (2) ◽  
pp. 125-160 ◽  
Author(s):  
John Daws
Keyword(s):  
Pressure Loss ◽  
Loss Rate ◽  
Inflation Pressure ◽  
Nitrogen Gas ◽  
Available Nitrogen ◽  
Passenger Car ◽  
Light Truck ◽  
Basic Model ◽  
Truck Tires ◽  
Selection Of

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.

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
Keyword(s):  
Pressure Loss ◽  
Loss Rate ◽  
Inflation Pressure ◽  
Rate Test ◽  
The Ideal

Tread Depth Effects on Tire Rolling Resistance

2001 ◽  
Vol 29 (3) ◽  
pp. 134-154 ◽  
Author(s):  
J. R. Luchini ◽  
M. M. Motil ◽  
W. V. Mars
Keyword(s):  
Finite Element Analysis ◽  
Common Knowledge ◽  
Rolling Resistance ◽  
Test Method ◽  
Tire Model ◽  
Element Analysis ◽  
Truck Tires ◽  
The Finite Element Analysis ◽  
Equilibrium Test ◽  
Depth Effects

Abstract This paper discusses the measurement and modeling of tire rolling resistance for a group of radial medium truck tires. The tires were subjected to tread depth modifications by “buffing” the tread surface. The experimental work used the equilibrium test method of SAE J-1269. The finite element analysis (FEA) tire model for tire rolling resistance has been previously presented. The results of the testing showed changes in rolling resistance as a function of tread depth that were inconsistent between tires. Several observations were also inconsistent with published information and common knowledge. Several mechanisms were proposed to explain the results. Additional experiments and models were used to evaluate the mechanisms. Mechanisms that were examined included tire age, surface texture, and tire shape. An explanation based on buffed tread radius, and the resulting changes in footprint stresses, is proposed that explains the observed experimental changes in rolling resistance with tread depth.

Determination of Steady-State Adhesive Wear Rate

2005 ◽  
Author(s):  
L. J. Yang
Keyword(s):  
Steady State ◽  
Wear Rate ◽  
Wear Test ◽  
Standard Test ◽  
Test Method ◽  
Testing Time ◽  
Wear Coefficient ◽  
Wear Rates ◽  
Test Methodology

Wear rates obtained from different investigators could vary significantly due to lack of a standard test method. A test methodology is therefore proposed in this paper to enable the steady-state wear rate to be determined more accurately, consistently, and efficiently. The wear test will be divided into four stages: (i) to conduct the transient wear test; (ii) to predict the steady-state wear coefficient with the required sliding distance based on the transient wear data by using Yang’s second wear coefficient equation; (iii) to conduct confirmation runs to obtain the measured steady-state wear coefficient value; and (iv) to convert the steady-state wear coefficient value into a steady-state wear rate. The proposed methodology is supported by wear data obtained previously on aluminium based matrix composite materials. It is capable of giving more accurate steady-state wear coefficient and wear rate values, as well as saving a lot of testing time and labour, by reducing the number of trial runs required to achieve the steady-state wear condition.

Application of Orthogonal Test in Numerical Simulation of Glass Lens Molding

2012 ◽  
Vol 497 ◽  
pp. 245-249
Author(s):  
Dao Cheng Zhang ◽  
Ke Jun Zhu ◽  
Yong Jian Zhu ◽  
Shao Hui Yin ◽  
Jian Wu Yu
Keyword(s):  
Process Parameters ◽  
Orthogonal Experiment ◽  
Fem Simulation ◽  
Orthogonal Test ◽  
Test Method ◽  
Testing Time ◽  
Molding Process ◽  
Glass Lens ◽  
Lens Molding ◽  
Process Factors

Glass lens molding is a high-volume fabrication method for producing optical components. In this paper, combined with the orthogonal test method and finite element method (FEM) simulation, the coupled thermo-mechanical analysis was carried out to analyze the key process factors. In order to reduce the testing time, an orthogonal test with three sets of level factors and three parameters is conducted to obtain the optimal molding process parameters. The result shows that the most significant parameter is molding velocity, the other effect parameters are molding temperature and friction coefficient. According to the previous analysis of orthogonal experiment, it is shown that the best optimal finishing process parameters were A2B1C1.

scholarly journals Fast Ways to Detect Outliers

2021 ◽  
Vol 3 (1) ◽  
pp. 66-73
Author(s):  
Emad Obaid Merza ◽  
Nashaat Jasim Mohammed
Keyword(s):  
Normal Distribution ◽  
Forest Fires ◽  
Confusion Matrix ◽  
Test Method ◽  
Z Score ◽  
Distribution Method ◽  
The Third ◽  
Data Points ◽  
Score Method ◽  
Zero Values

The occurrence of tremendous developments in the field of data has led to the formation of huge volumes of data, and it is normal that this leads to the presence of outliers in this data for many reasons, which may have small or large values ​​compared to the rest of the normal data, and the presence of outliers in the data affects the statistical analysis of this data, so we must try to reduce its impact in various ways. On the other hand, the presence of outliers ​​may be of great benefit, for example knowledge of geological activities that precede natural disasters such as (earthquakes, forest fires, floods ... etc.). Therefore, detection of outliers is of great importance in various fields. In this research, we aim to develop easy methods for detecting outliers in big data, as the problem that this research addresses is that many of the newly developed methods for detecting outliers suffer from computational complexity or are efficient when the sample size is small. An experimental approach was used in this research by suggesting three methods for detecting outliers, the first method is based on standard deviation and was tested and compared with the normal distribution method and the z-score method. The second method depends on the maximum and minimum value of the data, and the third method depends on the range between successive data points. The results of second and third methods are compared with Hample's Test method result. The accuracy of the results is measured based on the confusion matrix. The results of the proposed methods test showed the conformity of the first method with the results of the normal distribution method and the Z-Score method, as well as the superiority of the third method over the Hample's test method. In this paper, it was concluded that the Hample's test method suffers from a serious weakness when the zero values in the data constitute more than 50% of the number of elements.

An Experimentally Validated Model for Two-Phase Sudden Contraction Pressure Drop in Microchannel Tube Headers

2003 ◽  
Author(s):  
John Wesley Coleman
Keyword(s):  
Pressure Loss ◽  
Accurate Determination ◽  
Time Data ◽  
Two Phase ◽  
Pressure Transducers ◽  
Pressure Losses ◽  
Mass Fluxes ◽  
Data Points ◽  
Minor Losses ◽  
Phase Pressure

This paper presents the results of an experimental investigation of two-phase pressure loss of R134a in microchannel headers using various end-cut techniques. Novel experimental techniques and test sections were developed to enable the accurate determination of the minor losses without obfuscating the problem with a lengthwise pressure gradient. This technique represents a departure from approaches used by other investigators that have extrapolated minor losses from air-water experiments and the combined effects of expansion, contraction, deceleration, and lengthwise pressure gradients. Pressure losses were recorded over the entire range of qualities from 100% vapor to 100% liquid. In addition, the tests were conducted for five different refrigerant mass fluxes between 185 kg/m2-s and 785 kg/m2-s using two differnt end-cut techniques. More than 790 data points were recorded to obtain a comprehensive understanding of the effects of mass flux and quality on minor pressure losses. High accuracy instrumentation such as coriolis mass flowmeters, RTDs, pressure transducers, and real-time data analyses were used to ensure accuracy in the results. The results show that many of the commonly used correlations for estimating two-phase pressure losses significantly underpredict the pressure losses found in compact microchannel tube headers. Furthermore, the results show that the end-cut technique can substantially affect the pressure losses in microchannel headers. A new model for estimating the pressure loss in microchannel headers is presented and a comparison of the end-cut techniques on the minor losses is reported.

Statistical Distribution of Failure Stress Values from Superpave® Direct Tension Test

2002 ◽  
Vol 1810 (1) ◽  
pp. 72-77
Author(s):  
Raj Dongré ◽  
Charles Antle
Keyword(s):  
Weibull Distribution ◽  
Standard Test ◽  
Tension Test ◽  
Failure Stress ◽  
Test Method ◽  
Direct Tension ◽  
Data Set ◽  
Direct Tension Test ◽  
Data Points ◽  
Made In

A statistically robust method was developed using the Weibull distribution to identify and eliminate outliers from the failure stress determinations. The method is applicable to any failure stress data set that follows the Weibull distribution; however, in this application, it was developed for the AASHTO standard test method for conducting the direct tension test (DTT). A large number of stress-at-failure measurements with the DTT were made in the course of instructing users of this device. These data, all for the same asphalt, provided the means for studying the nature of the distribution of the breaking strength of these asphalt specimens. The training database contains more than 900 data points. The current AASHTO practice of eliminating the lowest two stress values was found to be reasonable. However, it is an arbitrary method that may lead to problems in the future. On the basis of the results of this study, the procedure is recommended for use and implementation in the next AASHTO version of the DTT standard.

Restrained Shrinkage Behavior of Concrete under Different Environmental Conditions

2014 ◽  
Vol 941-944 ◽  
pp. 835-841 ◽  
Author(s):  
Zhi Tao Chen ◽  
Mao Guang Li ◽  
Ying Zi Yang ◽  
Qi Liu
Keyword(s):  
Relative Humidity ◽  
Environmental Conditions ◽  
Test Method ◽  
Mineral Admixtures ◽  
Ring Test ◽  
Test Duration ◽  
Restrained Shrinkage ◽  
Shrinkage Cracking ◽  
Higher Temperature ◽  
Shrinkage Behavior

The ring test method is used to evaluate the behavior of concrete under restrained shrinkage. Four kinds of environmental conditions (20±1°C, RH60±5%; 35±1°C, RH60±5%; 50±1°C, RH15±5%; 65±1°C, RH15±5%) were designed to investigate the effect the environmental condition on the shrinkage behavior of concrete prepared with different kinds of mineral admixtures. The results show that higher temperature and lower relative humidity can increase the risk of shrinkage cracking. The addition of different mineral admixtures increases the shrinkage of concrete at room conditions. In the case of higher temperature and lower relative humidity, the addition of mineral admixtures can delay the shrinkage cracking in the test duration.

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