Friction properties of highly elastic materials at high contact pressures

1973 ◽  
Vol 7 (1) ◽  
pp. 115-120
Author(s):  
G. M. Bartenev ◽  
V. V. Lavrent'ev ◽  
V. S. Voevodskii
Keyword(s):  
Elastic Materials ◽  
Contact Pressures ◽  
Highly Elastic Materials

Flow Phenomena in Rubber Samples

1950 ◽  
Vol 23 (1) ◽  
pp. 67-88
Author(s):  
Fritz Rössler
Keyword(s):  
Low Temperatures ◽  
Test Specimen ◽  
Room Temperature ◽  
Elastic Materials ◽  
Dead Weight ◽  
Point Change ◽  
Different Types ◽  
Flow Phenomena ◽  
High Degree ◽  
Highly Elastic Materials

Abstract A more extended investigation was made of the surprising flow phenomena which were found in an earlier study of rubber at low temperatures. The tensile apparatus was reconstructed so that a dead-weight load could be applied to the rubber test-specimen. Determinations of the dependence of the rate of flow on time of stressing, initial elongation, magnitude of the stress, and temperature showed that a simple law can be derived for expressing the flow phenomena. Yield point, change in color, and deterioration in physical properties, as well as the reversibility of these phenomena were investigated and are discussed. The phenomena of flow at room temperature are expressed by the same constants as at lower temperatures. Only the effective stress increases at low temperatures and only by this change does flow become perceptible. Different types of rubber were compared, and all showed approximately the same value for the flow constant. The essential characteristics of the flow phenomenon can be explained, on a basis of the theory of highly elastic materials, by their microliquid state of aggregation. This applies to the high degree of dependence of the mechanical properties of rubber on the temperature.

Elastic deformation and the laws of friction

1957 ◽  
Vol 243 (1233) ◽  
pp. 190-205 ◽  
Keyword(s):  
Surface Topography ◽  
Elastic Deformation ◽  
Frictional Force ◽  
Metal Surfaces ◽  
Applied Load ◽  
Elastic Contact ◽  
Elastic Materials ◽  
General Law ◽  
Highly Elastic Materials

This paper examines whether the hypothesis of elastic deformation of surface protuberances is consistent with Amontons’s law, that the friction is proportional to the applied load. For a single elastic contact, the area of contact A is known to be proportional to the ⅔ power of the load W . Since the frictional force is generally assumed to be proportional to A , it has been thought that in elastic deformation Amontons’s law would not be obeyed. However, conforming surfaces usually touch at many points, and it is shown that in these circumstances A and W become nearly proportional. Experiments are described which show that the general law is that the friction is proportional to the true area of contact; whether or not Amontons’s law is obeyed depends upon the surface topography. For highly elastic materials such as Perspex, Amontons’s law is obeyed when contact is made at many points, and other relations between A and W are observed when the contacts are few. Experiments with lubricated brass specimens show that the same conclusions apply to carefully prepared or well run-in metal surfaces running in conditions where the damage is small.

Measuring deformations of highly elastic materials with resistance strain gauges

1969 ◽  
Vol 12 (2) ◽  
pp. 203-205 ◽  
Author(s):  
A. B. Zlochevskii ◽  
V. I. Mironov
Keyword(s):  
Resistance Strain ◽  
Strain Gauges ◽  
Elastic Materials ◽  
Highly Elastic Materials

The strength of highly elastic materials

1967 ◽  
Vol 300 (1460) ◽  
pp. 108-119 ◽  
Keyword(s):  
Chemical Structure ◽  
Unit Area ◽  
Strength Properties ◽  
Polymer Chains ◽  
Chemical Bonds ◽  
Elastic Materials ◽  
Chemical Corrosion ◽  
Vulcanized Rubber ◽  
Theory And Experiment ◽  
Highly Elastic Materials

Under repeated stressing, cracks in a specimen of vulcanized rubber may propagate and lead to failure. It has been found, however, that below a critical severity of strain no propagation occurs in the absence of chemical corrosion. This severity defines a fatigue limit for repeated stressing below which the life can be virtually indefinite. It can be expressed as the energy per unit area required to produce new surface ( T 0 ), and is about 5 x 10 4 erg/cm 2 . In contrast with gross strength properties such as tear and tensile strength, T 0 does not correlate with the viscoelastic behaviour of the material and varies only relatively slightly with chemical structure. It is shown that T 0 can be calculated approximately by considering the energy required to rupture the polymer chains lying across the path of the crack. This energy is calculated from the strengths of the chemical bonds, secondary forces being ignored. Theory and experiment agree within a factor of 2. Reasons why T 0 and the gross strength properties are influenced by different aspects of the structure of the material are discussed.

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