Methods of testing vulcanized rubber. Determination of compression stress-strain

1957 ◽  
Keyword(s):  
Compression Stress ◽  
Stress Strain ◽  
Vulcanized Rubber

Thermodynamics of Crystallization in High Polymers. VI. Incipient Crystallization in Stretched Vulcanized Rubber

1950 ◽  
Vol 23 (3) ◽  
pp. 576-580 ◽  
Author(s):  
Thomas G. Fox ◽  
Paul J. Flory ◽  
Robert E. Marshall
Keyword(s):  
Theoretical Prediction ◽  
Experimental Determination ◽  
Strain Curve ◽  
Steep Slope ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Hydrostatic Method ◽  
Vulcanized Rubber ◽  
High Polymers

Abstract Experimental determination of the elongation at which crystallization commences in vulcanized rubber has been attempted through measurement of density changes by a hydrostatic method. The critical elongation for incipient crystallization appears to depend on the temperature, in approximate accordance with theoretical prediction. Crystallization sets in at an elongation well below that at which the stress-strain curve assumes a steep slope.

Comparative Experimental Analysis of Different Bending Methods for the Mechanical Characterization of Materials with Previous Loading History (Stress-Strain Curves)

2011 ◽  
Vol 314-316 ◽  
pp. 1377-1382
Author(s):  
David Torres Franco ◽  
Guillermo Urriolagoitia-Sosa ◽  
Guillermo Urriolagoitia-Calderón ◽  
Luis Hector Hernandez Gomez ◽  
Beatriz Romero Angeles ◽  
...  
Keyword(s):  
Simultaneous Determination ◽  
Compression Stress ◽  
Loading History ◽  
Stress Strain ◽  
Axial Tensile ◽  
Tension And Compression ◽  
Characterization Of Materials ◽  
Previous Loading

Until now, the most common way to obtain the stress-strain curves for a material is through axial tensile testing. However, in recent years there have been developments on alternative methods for material characterization. In this sense, the bending procedure has proved to be a powerful technique, which allows simultaneous determination of tension and compression stress behavior by the use of bending moment and strain data. The characterization of materials by means of bending data was presented for the first time in 1910 by the German engineer Herbert. Some years later Nadai and Marin developed some research on this procedure. More recently, several researchers (Mayville and Finnie, Laws and Urriolagoitia-Sosa, et.al.) have developed diverse bending methods for the simultaneous determination of tension and compression stress-strain curves. In this paper, three bending methods are analyzed and compared against axial tensile and compressive results. It was decided to apply each one of the bending procedures to bent rectangular cross sections beams made from 6063-T5 Aluminum alloy. The specimens were annealed to eliminate previous loading history and axially pulled to induce a controlled anisotropic behavior (strain hardening and Bauschinger effect). The results obtained by two of the three methods provided great confidence and have certified the application of this new technique to characterize material.

The Influence of the Test-Specimen on the Results Obtained In Tensile Tests of Soft Vulcanized Rubber Mixtures

1953 ◽  
Vol 26 (2) ◽  
pp. 465-480
Author(s):  
R. Herzog ◽  
R. H. Burton
Keyword(s):  
Natural Rubber ◽  
Tensile Properties ◽  
Test Specimen ◽  
Tensile Tests ◽  
Stress Strain ◽  
Vulcanized Rubber ◽  
Different Types ◽  
Small Test ◽  
Soft Rubber

Abstract The small test-specimen of the VSM-1 type should not be used for measuring the tensile properties of pure-gum vulcanizates; instead, the VSM-1a type of test-specimen should be used for such vulcanizates. Results obtained with the different types of test-specimen differ greatly; hence, in reporting the results of any tests of this kind, the type of test-specimen used should be stated, and only results obtained with one particular type of test-specimen should be compared. For example, substitution of the VSM-2 type of test-specimen by the KTA-II type of test-specimen, which is of approxmately the same size, unfortunately does not result in any better agreement. Based on these differences, which in the case of natural rubber have been found to vary from one type of vulcanizate to another, it is natural to expect corresponding unpredictable differences with various synthetic elastomers. The determination of stress-strain properties of soft rubber vulcanizates is, therefore, fundamentally a problem of agreement on methods of testing, i.e., of standardization.

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