Variations in Tire Hysteretic Losses Due to Tire Design

1974 ◽  
Vol 47 (1) ◽  
pp. 118-126 ◽  
Author(s):  
P. R. Willett
Keyword(s):  
Thermal Equilibrium ◽  
Viscoelastic Properties ◽  
Design Stage ◽  
Energy Losses ◽  
Operating Parameters ◽  
Stress Strain ◽  
Passenger Car ◽  
Truck Tires

Abstract The technique of analyzing energy losses of tires that have reached a state of thermal equilibrium has been applied to cross-ply and radial-ply passenger car tires and cross-ply truck tires. The derived formulations relating the tire energy losses to the viscoelastic properties of the tire components show the dependence of these losses on tire size and construction. The analysis was carried out by systematically varying tire tread compounds and operating parameters. This investigation of the energy losses experienced by tires operating in a state of thermal equilibrium, has enabled the losses due to the various stress-strain deformations to be characterized. In particular, the losses due to the strain deformation have been correlated with two mechanisms, which are outlined. The results described enable a better understanding of the mechanisms responsible for tire energy losses and allow the tire losses to be predicted at the design stage.

Hysteretic Losses in Rolling Tires

1973 ◽  
Vol 46 (2) ◽  
pp. 425-441 ◽  
Author(s):  
P. R. Willett
Keyword(s):  
Thermal Equilibrium ◽  
Viscoelastic Properties ◽  
Constant Speed ◽  
Energy Losses ◽  
Operating Parameters ◽  
Tire Cord ◽  
Service Characteristics

Abstract A relationship between the observed energy losses for a tire that has reached a state of thermal equilibrium when operating at a constant speed, and the viscoelastic properties of the tire components has been formulated. The analysis was carried out by systematically varying tire components and operating parameters, using the Vibron Viscoelastometer and tire test wheel dynamometer. The investigation was carried out for 6.95–14 cross ply passenger tires. From the derived dependence of the tire energy losses on viscoelastic properties, the effect of changes in tire tread compound, ply rubber and tire cord on the tire energy losses can be predicted. This enables the design of a tire with the properties to meet desired service characteristics.

Heat Generation in Tires Due to the Viscoelastic Properties of Elastomeric Components

1974 ◽  
Vol 47 (2) ◽  
pp. 363-375 ◽  
Author(s):  
P. R. Willett
Keyword(s):  
Multiple Regression ◽  
Heat Generation ◽  
Thermal Equilibrium ◽  
Viscoelastic Properties ◽  
Stress Amplitude ◽  
Truck Tires ◽  
Shoulder Region ◽  
Response Equation ◽  
The Subject ◽  
The Relationship

Abstract The relationship between the heat generation as experienced in the tire shoulder and the viscoelastic properties of the tire elastomeric components has been formulated. The analysis was facilitated by adopting the technique of multiple regression where the significance of each response equation was statistically evaluated. The physical intepretation and consequences of such response equations have been extensively discussed, whereas literature on the subject is incomplete. Effects of tire construction and size on the heat generation in the shoulder region was carried out by analyzing the results of tires that had reached a state of thermal equilibrium on an indoor tire-dynamometer. The tires used in the analysis were cross-ply and radial-ply passenger tires and cross-ply truck tires. Within the limits of such an analysis, the heat generation experienced in the tire shoulder was predominantly due to the condition classified as that of constant stress amplitude.

MODELING OF THE STRESS-STRAIN STATE OF A TRANSPORT TUNNEL UNDER LOAD AS A MEASURE TO REDUCE OPERATIONAL RISKS TO TRANSPORTATION FACILITIES

2020 ◽  
Vol 3 (8) ◽  
pp. 28-34
Author(s):  
N. V. IVANITSKAYA ◽  
◽  
A. K. BAYBULOV ◽  
M. V. SAFRONCHUK ◽  
◽  
...  
Keyword(s):  
Strain State ◽  
Moving Load ◽  
Element Model ◽  
Transport Infrastructure ◽  
Design Stage ◽  
Surface Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Operational Risks ◽  
Von Mises

In many countries economic policy has been paying increasing attention to the modernization and development of transport infrastructure as a measure of macroeconomic stimulation. Tunnels as an important component of transport infrastructure save a lot of logistical costs. It stimulates increasing freight and passenger traffic as well as the risks of the consequences of unforeseen overloads. The objective of the paper is to suggest the way to reduce operational risks of unforeseen moving load by modeling of the stress-strain state of a transport tunnel under growing load for different conditions and geophysical parameters. The article presents the results of a study of the stress-strain state (SSS) of a transport tunnel exposed to a mobile surface load. Numerical experiments carried out in the ANSYS software package made it possible to obtain diagrams showing the distribution of equivalent stresses (von Mises – stresses) according to the finite element model of the tunnel. The research results give grounds to assert that from external factors the stress state of the tunnel is mainly influenced by the distance to the moving load. The results obtained make it possible to predict in advance the parameters of the stress-strain state in the near-contour area of the tunnel and use the results in the subsequent design of underground facilities, as well as to increase their reliability and operational safety. This investigation gives an opportunity not only to reduce operational risks at the design stage, but to choose an optimal balance between investigation costs and benefits of safety usage period prolongation.

Viscoelastic Properties of PVB Interlayer for Laminated Glass Structures Used in Building Reconstructions

2019 ◽  
Vol 808 ◽  
pp. 115-122
Author(s):  
Miroslav Vokáč ◽  
Tomáš Hána ◽  
Klára V. Machalická ◽  
Martina Eliášová
Keyword(s):  
Viscoelastic Properties ◽  
Thermoplastic Polyurethane ◽  
Maxwell Model ◽  
Polyvinyl Butyral ◽  
Laminated Glass ◽  
Building Structures ◽  
Structural Element ◽  
Stress Strain ◽  
Existing Building ◽  
Material Parameters

Laminated glass is a structural element used extensively in a reconstruction of existing building structures because of its transparency and simplicity. When using laminated glass as a glass staircase, balustrades, transparent flooring, facades or other structural elements, it is advisable to consider the shear interaction of individual glass panes in the cross-section. A conservative approach where the glass panes shear interaction is not considered, is uneconomical. This interaction depends on the properties of polymeric interlayers used in lamination process. Various commercial products based on PVB (polyvinyl butyral), EVA (ethylene vinyl acetate), ionomer, or thermoplastic polyurethane (TPU) are used. Stiffness of polymers depends on temperature and duration of a load. Interlayers exhibit the viscoelastic properties and temperature dependency usually described by the generalized Maxwell model and WLF model (Williams-Landel-Ferry). Parameters of these models are the most effectively determined by Dynamic Mechanical Thermal Analysis (DMTA), where the material is cyclically loaded at different frequencies and temperatures. Material parameters were found by DMTA in shear for PVB type of interlayer Trosifol® BG R20. In addition, the experimental quasi-static loading tests in shear were performed at different loading rates and at various temperatures. These experimental stress-strain diagrams were compared to the theoretical stress-strain relations obtained from Maxwell model with material parameters based on DMTA testing. All tests were performed in Klokner Institute CTU in Prague.

The Time and History-Dependent Viscoelastic Properties of the Canine Medial Collateral Ligament

1981 ◽  
Vol 103 (4) ◽  
pp. 293-298 ◽  
Author(s):  
S. L.-Y. Woo ◽  
M. A. Gomez ◽  
W. H. Akeson
Keyword(s):  
Medial Collateral Ligament ◽  
Viscoelastic Properties ◽  
Cyclic Stress ◽  
Elastic Response ◽  
Collateral Ligament ◽  
Stress Strain ◽  
Linear Viscoelastic ◽  
Viscoelastic Theory ◽  
Linear Viscoelastic Theory

The viscoelastic properties of the canine medial collateral ligament (MCL) were investigated. Stress-strain relationships at different strain rates, long-term stress relaxation and cyclic stress-strain curves of the MCL were obtained experimentally using a bone-MCL-bone preparation. The experimental data were used in conjunction with the quasi-linear viscoelastic theory as proposed by Fung [15] to characterize the reduced relaxation function, G(t) and elastic response σe (ε) of this tissue. It was found that the quasi-linear viscoelastic theory can adequately describe the time and history-dependent rheological properties of the canine medial collateral ligament.

scholarly journals DESIGN AND CONSTRUCTION OF LINEAR MAIN PIPELINE ON WATER-LOGGED GROUNDS

2020 ◽  
Vol 22 (6) ◽  
pp. 167-176
Author(s):  
V. I. Khizhnyakov ◽  
A. V. Negodin ◽  
V. A. Shelkov ◽  
A. N. Toz
Keyword(s):  
Temperature Difference ◽  
Strain State ◽  
Design Stage ◽  
Main Pipeline ◽  
Axial Loads ◽  
Stress Strain ◽  
Stress Strain State ◽  
Main Pipelines ◽  
Buckling Stability ◽  
Design And Construction

The paper shows that the linear segments of the main pipelines laid on water-logged grounds are characterized by the floating parts 150–300 m long, with arch blowouts with a deflection of 1.0–1.5 m. This occurs due to the vertical axial loads and the temperature difference. The buckling stability of the floating part is calculated for the pipeline laid in a bog. It is shown that the loss of the buckling stability in the form of the floating parts and arch blowout can be explained by the fact that the project on the water-logged ground construction has no the analysis of the buckling stability under axial loads with regard to the topography of the trench bottom that describes the stress-strain state of the pipeline. At a design stage, it is necessary to conduct more detailed surveys on the pipeline laying with regard to the trench profile in calculating the pipeline buckling stability on water-logged grounds.

scholarly journals Analysis of the geometry and contact density of globoid gearing

2020 ◽  
Vol 329 ◽  
pp. 03008
Author(s):  
Aleksandr Vyatkin
Keyword(s):  
Numerical Methods ◽  
Load Capacity ◽  
High Load ◽  
Design Stage ◽  
Energy Losses ◽  
Technological Parameters ◽  
Contact Density ◽  
Small Energy ◽  
Worm Gears ◽  
High Load Capacity

Globoid worm gears have been widely applied in a range of technological branches in which other types of worm gears are less effective. The main functional indicators which facilitated their popularity include high load capacity and durability, low vibroactivity and small energy losses. As the experience of application and the results of the study of globoid worm gears showed, the level of operational properties of globoid gears is higher than that of the others only if the gearing and technological parameters of their manufacturing are optimally chosen during the design stage. This paper describes a method for estimating the gearing parameters of a globoid gear with an account of the geometry of the elements (the geometry of the teeth of the wheel and the worm thread), namely the calculation of the gap fields in the globoid gearing by means of numerical methods.

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