Indoor Test Procedures for Evaluation of Tire Treadwear and Influence of Suspension Alignment

1989 ◽  
Vol 17 (4) ◽  
pp. 236-273 ◽  
Author(s):  
S. Yamazaki ◽  
T. Fujikawa ◽  
A. Hasegawa ◽  
S. Ogasawara
Keyword(s):  
Wear Rate ◽  
Wear Test ◽  
Test Results ◽  
Road Test ◽  
Test Procedures ◽  
Test Conditions ◽  
Camber Angle ◽  
Toe Angle ◽  
Straight Ahead ◽  
Automobile Tires

Abstract Laboratory wear test procedures for automobile tires are described, as are the influences of alignments such as camber angle and toe angle. Ply-steer and conicity were considered in determining slip angles in straight-ahead rolling on a drum. Wear patterns produced by different alignment configurations simulated the range of patterns observed in road tests. This, together with good wear rate comparisons, supports our belief that road-test conditions are sufficiently reproducible in the laboratory to yield valid wear test results.

Rubber Abrasion and Tire Wear

2008 ◽  
Vol 81 (3) ◽  
pp. 470-505 ◽  
Author(s):  
K. A. Grosch
Keyword(s):  
Contact Area ◽  
Limited Range ◽  
Laboratory Method ◽  
Test Results ◽  
Road Test ◽  
Test Conditions ◽  
Wide Range ◽  
Single Compound ◽  
Tearing Energy ◽  
Energy Dissipated

Abstract Rubber abrasion is essentially a mechanical tearing process and has been linked with the rate of a cut growth process as function of the tearing energy dissipated in the contact area between rubber and track which leads inevitably to considerable temperature rises at the points of highest stress concentration i.e. at the points at which a mechanical detachment of abraded particles is most likely. This leads to thermal degradation and oxidation as important secondary mechanisms which may well decide whether a compound performs better or worse than a reference outweighing the mechanical properties. A laboratory method has been developed, using the LAT 100 test equipment, which uses the energy dissipation and slip speeds in the contact area of a rubber sample wheel, rotating under slip, to evaluate the abrasion performance of a compound over a wide range of these variables. The resulting equations can be used either to test directly the correlation between laboratory and road test results which is usually good over a limited range, or they are used in a road test simulation program with well defined road test conditions. The latter gives a set of single compound ratings and tire lives. These depend however strongly on the chosen test conditions and in that they reflect reality

Does Thermal Conductivity Play a Role in Sliding Wear of Metals in Cryogenic Environment?

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Bikramjit Basu ◽  
Amartya Mukhopadhyay ◽  
Ankit Mishra ◽  
J. Sarkar
Keyword(s):  
Thermal Conductivity ◽  
Wear Rate ◽  
Sliding Wear ◽  
Friction And Wear ◽  
Wear Test ◽  
Dry Sliding Wear ◽  
Oxidative Wear ◽  
Wear Properties ◽  
Wear Rates ◽  
Test Conditions

The thermal conductivity of a metallic test piece is one of the principal parameters that influence the temperature buildup at tribocontacts and this normally plays an important role in the unlubricated dry sliding wear of metallic materials. It is, however, not clear whether thermal conductivity is an equally important parameter in the case of wear of metals at cryogenic temperatures, in particular, at liquid nitrogen temperature (LN2) of −196°C. In order to assess the influence of such a physical property of selected nonferrous metals on their tribological behavior in the LN2 environment, we have studied the friction and wear properties of high purity copper (Cu) and titanium (Ti) against the bearing grade steel. These two materials have been processed to produce samples of comparable hardness that have widely different thermal conductivities at room temperature and at test temperature. Wear tests were conducted at three different sliding speeds (0.89 m/s, 1.11 m/s, and 1.34 m/s) under 10 N load, and the friction and wear data were compared. Ti exhibited an order of magnitude higher wear rate (∼10−3 mm3/N m) as compared with Cu in identical test conditions. While evidences of abrasive wear and adhesive wear, without any oxidative wear, were found in worn Cu surfaces, worn Ti surfaces showed evidences of significant oxidative wear and mechanical damage of tribolayers. Higher wear rate in Ti appeared to be a result of oxidative wear of Ti, which seemed to be driven by the depletion of LN2 blanket at the tribocontacts under the influence of high flash temperature (14–76°C) as compared with the boiling temperature of LN2(−196°C). These results demonstrate that the materials with similar hardness subjected to identical LN2 wear test conditions can have significantly different wear rates because of the difference in the flash temperatures, which depend on the thermal conductivity of the test pieces.

scholarly journals Wear Analysis of an Advanced Al–Al2O3 Composite Infiltrated with a Tin-Based Alloy

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1692
Author(s):  
Mihail Kolev ◽  
Ludmil Drenchev ◽  
Veselin Petkov
Keyword(s):  
Wear Rate ◽  
Hybrid Material ◽  
Sliding Friction ◽  
Wear Behavior ◽  
Wear Test ◽  
Specific Wear Rate ◽  
Dry Sliding ◽  
Test Conditions ◽  
The Coefficient Of Friction ◽  
En 31

In this study, a hybrid material is produced, and the effect of different loads varying from 40 to 60 N against an EN-31 steel counter disk on its wear behavior under dry sliding conditions at room temperature is studied. The tribological behavior is studied via the pin-on-disk method and analyzed using primary wear parameters, such as the coefficient of friction (COF), mass wear, and specific wear rate. The obtained results are compared with the results for B83 babbitt under the same wear test conditions. Microstructural observation with scanning electron microscopy (SEM) is performed along with X-ray energy dispersive spectroscopy (EDX) for chemical analysis conduction. The results from the wear experiments indicate that the hybrid material possesses a lower COF, mass wear, and specific wear rate as well as a higher wear resistance in comparison to the B83 babbitt specimen when subjected to the same test conditions. The results from the wear experiments indicate that by applying different loads of 40, 50, and 60 N, the hybrid material possesses a lower mass wear, specific wear rate, and COF specifically at a load of 40 N in comparison to the B83 babbitt specimen under the same test conditions. It was also observed that by increasing the load under dry sliding friction, the hybrid material increases its mass wear and specific wear rate.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

scholarly journals Influence of Test Conditions on Sliding Wear Performance of High Velocity Air Fuel-Sprayed WC–CoCr Coatings

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3074
Author(s):  
Kaveh Torkashvand ◽  
Vinod Krishna Selpol ◽  
Mohit Gupta ◽  
Shrikant Joshi
Keyword(s):  
Wear Rate ◽  
Test Performance ◽  
Sliding Wear ◽  
Normal Load ◽  
Specific Wear Rate ◽  
Wear Behaviour ◽  
Wear Performance ◽  
Test Conditions ◽  
Test Parameters ◽  
Sliding Distance

Sliding wear performance of thermal spray WC-based coatings has been widely studied. However, there is no systematic investigation on the influence of test conditions on wear behaviour of these coatings. In order to have a good understanding of the effect of test parameters on sliding wear test performance of HVAF-sprayed WC–CoCr coatings, ball-on-disc tests were conducted under varying test conditions, including different angular velocities, loads and sliding distances. Under normal load of 20 N and sliding distance of 5 km (used as ‘reference’ conditions), it was shown that, despite changes in angular velocity (from 1333 rpm up to 2400 rpm), specific wear rate values experienced no major variation. No major change was observed in specific wear rate values even upon increasing the load from 20 N to 40 N and sliding distance from 5 km to 10 km, and no significant change was noted in the prevailing wear mechanism, either. Results suggest that no dramatic changes in applicable wear regime occur over the window of test parameters investigated. Consequently, the findings of this study inspire confidence in utilizing test conditions within the above range to rank different WC-based coatings.

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.

Answering the Questions of the Psychologist Assessing the Visually Handicapped Child

1975 ◽  
Vol 69 (8) ◽  
pp. 350-353
Author(s):  
John L. Morse
Keyword(s):  
Classroom Observation ◽  
Handicapped Child ◽  
Test Results ◽  
Visual Condition ◽  
Inappropriate Behaviors ◽  
Test Conditions ◽  
Visually Handicapped ◽  
First Time

The most common question asked by the psychologist who is faced for the first time with assessing a visually handicapped child are answered. The 15 questions include such areas as the required information concerning visual condition, background of the client, test conditions, the role of the parents, classroom observation, behaviors observed during testing, evaluation of test results, expectations of parents and teachers, and modification of a child's inappropriate behaviors.

Drive and Brake Joint Control of Acceleration Slip Regulation Road Test

2014 ◽  
Vol 971-973 ◽  
pp. 454-457
Author(s):  
Gang He ◽  
Li Qiang Jin
Keyword(s):  
Front Wheel ◽  
Driving Ability ◽  
Joint Control ◽  
Test Results ◽  
Road Test ◽  
Wheel Slip ◽  
Traction Control ◽  
Wheel Drive ◽  
Driving Wheel ◽  
Independent Design

Based on the independent design front wheel drive vehicle traction control system (TCS), we finished the two kinds of working condition winter low adhesion real vehicle road test, including homogenous pavement and separate pavement straight accelerate, respectively completed the contrastive experiment with TCS and without TCS. Test results show that based on driver (AMR) and brake (BMR) joint control ASR system worked reliably, controlled effectively, being able to control excessive driving wheel slip in time, effectively improved the driving ability and handling stability of vehicle.

scholarly journals Simulation of loop test conditions for the modified SM reactor fuel rods and test results in justification of their performance

2013 ◽  
Vol 2013 (2) ◽  
pp. 105-113
Author(s):  
Vladimir Aleksandrovich Starkov ◽  
Fedoseev V.E. Fedoseev ◽  
Shishin V.Yu. Shishin
Keyword(s):  
Reactor Fuel ◽  
Test Results ◽  
Fuel Rods ◽  
Test Conditions

Experimental characterization of composites to support an orthotropic plasticity material model

2017 ◽  
Vol 52 (14) ◽  
pp. 1847-1872 ◽  
Author(s):  
Bilal Khaled ◽  
Loukham Shyamsunder ◽  
Canio Hoffarth ◽  
Subramaniam D Rajan ◽  
Robert K Goldberg ◽  
...  
Keyword(s):  
Material Model ◽  
Unidirectional Composite ◽  
Deformation Model ◽  
Test Results ◽  
Dynamic Impact ◽  
Test Procedures ◽  
Stress Strain ◽  
Damage And Failure ◽  
Orthotropic Behavior

Test procedures for characterizing the orthotropic behavior of a unidirectional composite at room temperature and quasi-static loading conditions are developed and discussed. The resulting data consisting of 12 stress–strain curves and associated material parameters are used in a newly developed material model—an orthotropic elasto-plastic constitutive model that is driven by tabulated stress–strain curves and other material properties that allow for the elastic and inelastic deformation model to be combined with damage and failure models. A unidirectional composite—T800/F3900, commonly used in the aerospace industry, is used to illustrate how the experimental procedures are developed and used. The generated data are then used to model a dynamic impact test. Results show that the developed framework implemented into a special version of LS-DYNA yields reasonably accurate predictions of the structural behavior.

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