Tensile Tests with Flat (Straight) Test-Specimens

1938 ◽  
Vol 11 (1) ◽  
pp. 214-223
Author(s):  
R. Ariano
Keyword(s):  
Test Specimen ◽  
Testing Machine ◽  
American Chemical Society ◽  
Tensile Tests ◽  
Chemical Society ◽  
Ring Test ◽  
Rubber Ring ◽  
Long Time ◽  
Fundamental Objection ◽  
Center Section

Abstract It is of course a well known fact that both ring test-specimens and flat or straight test-specimens are used in testing rubber. Ring test-specimens have for a long time been the most generally used type for testing rubber mixtures, whereas in American laboratories straight test-specimens are preferred. Ring test-specimens are the more convenient to use, but they are open to one fundamental objection, that different parts of the cross section of the rubber are elongated to different extents at any particular moment. Even straight test-specimens are not free from objectionable features. With this type of test-specimen, the inequality in the deformation at any particular instant results from the necessity of having enlarged ends for the testing machine to avoid breakage of the test-specimens in the jaws. It therefore becomes necessary to study systematically the form and dimensions of the end sections of the test-specimens and of the junction of these end sections with the central section, so that the points of rupture will not become localized in the sections in the jaws or close to these sections. As a matter of fact, an extensive investigation of this problem has been made by the Physical Testing Committee of the Rubber Division of the American Chemical Society. By a proper study of the shape of the test-specimen, it is possible to design the test-specimen so that rupture occurs in the center section and therefore so that satisfactory tensile strength measurements are obtained.

Tensile Tests of Plantation Rubber

1940 ◽  
Vol 13 (3) ◽  
pp. 451-467
Author(s):  
I. Slbiriakoff
Keyword(s):  
American Chemical Society ◽  
Tensile Tests ◽  
Chemical Society ◽  
Testing Procedure ◽  
Ring Test ◽  
Open Steam ◽  
Fixed Weight ◽  
Roll Temperature ◽  
Commercial Testing ◽  
The Tropics

Abstract The investigation which has just been described can be summarized as follows: (1) A technique for the commercial testing of plantation rubber has been developed which is simple and precise, and by means of which it is possible to reproduce control tests, a feature which is indispensable if rubber is to be sold on a basis of quality rather than superficial appearance. (2) The tentative specifications for testing rubber drawn up by the Crude Rubber Committee of the Division of Rubber Chemistry of the American Chemical Society have been found acceptable as a basis for this testing procedure. (3) It has been found necessary, however, to revise the specifications of the Crude Rubber Committee in some ways and to amplify them, so that they fulfill the three conditions described above and also conform to the particular working conditions of laboratories in the tropics. The revisions to the Crude Rubber Committee specifications include: (1) The use of an autoclave for vulcanizing in open steam. (2) A mill roll temperature of 65° C instead of 70° C. (3) A definite, fixed weight of batch, containing 200 grams of rubber, plus accessory ingredients. (4) A temperature of 25° to 30° C during testing. (5) The use of ring test-specimens instead of dumb-bell specimens.

Physical Testing of Latex Films

1937 ◽  
Vol 10 (3) ◽  
pp. 584-614 ◽  
Author(s):  
C. F. Flint ◽  
W. J. S. Naunton
Keyword(s):  
Testing Machine ◽  
Water Soluble ◽  
Ring Test ◽  
Thick Sheet ◽  
Tensile Testing Machine ◽  
Test Pieces ◽  
Physical Testing ◽  
Long Time ◽  
Soluble Components ◽  
Latex Rubber

Abstract Determinations of the tensile strength of latex rubber involve difficulties which concern either the preparation of the sheets or the technic used in breaking them. Thick sheets of latex rubber may be cut into dumb-bell or ring test-pieces, which may then be broken on a tensile-testing machine of normal type. The preparation of thick sheets is, however, a matter of difficulty, owing to the fact that the complete drying-off of the water takes such a long time. Thus when ultra-accelerators are under test, vulcanization of the sheets may be advanced, or even complete, before the sheets are dry, so that investigation of the early stages of cure is impossible. Further, during the time that elapses before evaporation has gelled the whole thickness of latex, sedimentation of the compounding ingredients may occur in the mass of the fluid sheet, resulting in vulcanizates which are not uniform in composition or degree of cure. The use of devices such as porous tiles or the expedient of flowing the latex onto the surface of a gelatin jelly is objectionable because they absorb water-soluble components as well as water from the latex mix. Further, although they tend to prevent sedimentation by promoting more rapid gelling, the complete elimination of the water from a thick sheet is still a lengthy process, during which complete self-vulcanization may easily occur. The use of chemical coagulants is open to the same objection, which is of course overshadowed by the much more serious obstacle of their effect on the activity of accelerators and on the physical properties of the latex rubber.

A Short Note on the Tensile Testing of Rubber

1932 ◽  
Vol 5 (3) ◽  
pp. 351-355 ◽  
Author(s):  
M. Jones
Keyword(s):  
Tensile Strength ◽  
Tensile Testing ◽  
Short Note ◽  
American Chemical Society ◽  
Chemical Society ◽  
Ring Test ◽  
Stress Strain ◽  
Test Pieces ◽  
The One

Abstract The evaluation of rubber has centered largely around stress-strain phenomena, and the property of tensile strength is probably the one which has the most general application throughout the industry. Rubber exhibits stress-strain properties quite different from the majority of substances, and peculiar difficulties are introduced during the determination of tensile strength. Although tentative standards have recently been issued by the American Chemical Society, there is no evidence that these are being strictly adhered to, and there is still need for a more rigid standardization of tensile-testing methods. There are essentially two methods of tensile-testing: (1) Using dumb-bell test-pieces with a Bureau of Standards machine, or a Scott type of machine; and (2) Using ring test-pieces with a Schopper type of machine. It is generally supposed that higher tensile results are obtained by the former method. Recently, occasion has occurred to make a comparison between both types and to study the effect of certain factors upon each method.

Design of Threaded Fatigue Test Specimen for Machining

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Hamza K. Akyildiz ◽  
Haydar Livatyali
Keyword(s):  
Fatigue Test ◽  
Test Section ◽  
Test Specimen ◽  
Fatigue Testing ◽  
Complex Geometry ◽  
Testing Machine ◽  
High Strength ◽  
Critical Test ◽  
Fatigue Notch Factor ◽  
Center Section

Design and machining of the fatigue test specimens have significant effects on the duration and reliability of fatigue test. Fatigue test specimens essentially consist of three parts: the center or critical test section, which is the region where required conditions are simulated as closely as possible, and the two ends, which serve to transfer the load from the grips to the center section. When high strength materials are used for a complex geometry, such as a thread need to be tested, design and manufacturing of the specimens become more influential on the reliability and duration of the tests. Threaded fatigue test specimens were designed, machined, and tested in a four-point rotary bending fatigue testing machine. An innovative threaded fatigue test specimen that consistently fails at the critical test section was designed, machined, and tested successfully to give the required fatigue notch factor. Because of full scale fatigue testing with threaded parts is very expensive and sometimes dangerous, evaluated threaded fatigue specimen can be used in fatigue testing and it reduces duration of the experiment more than 60% for machined threaded specimens.

Graphical Tensile-Testing Machine for Rubber Threads

1931 ◽  
Vol 4 (3) ◽  
pp. 456-463
Author(s):  
S. H. Hahn ◽  
E. O. Dieterich
Keyword(s):  
Testing Machine ◽  
Strain Curve ◽  
Tensile Tests ◽  
Woven Fabric ◽  
Ring Test ◽  
Tensile Testing Machine ◽  
Factory Production ◽  
Physical Testing ◽  
The Common ◽  
The Many

Abstract AMONG the many types of physical testing equipment which have been designed for or applied to the needs of the rubber industry, there has never appeared an entirely satisfactory graphical machine for performing tensile tests on small rubber samples, such as the threads and tapes used in making golf balls and elastic fabrics and cords. None of the common machines can be applied directly to the testing of single threads, and even tests on pieces of dumbbell shape are quite unsatisfactory, largely because the standard machines are comparatively insensitive at low elongations and tensions and also because they depend on the personal accuracy of an operator to observe several points along the stress-strain curve. The Schopper ring test is not entirely successful for tests on threads. Accordingly it appeared that such tests on light rubber threads could best be made on a curve-drawing machine, designed and constructed especially for the purpose. In many cases, the use of any other machine would have been impossible because frequent tests had to be run on single, cut threads from factory production and on samples taken from storage or from woven fabric.

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM

2020 ◽  
Author(s):  
MAK Williams ◽  
V Cornuault ◽  
AH Irani ◽  
VV Symonds ◽  
J Malmström ◽  
...  
Keyword(s):  
Average Length ◽  
American Chemical Society ◽  
Md Simulations ◽  
Chemical Society ◽  
Side Chains ◽  
Rhamnogalacturonan I ◽  
Afm Imaging ◽  
Minor Population ◽  
The Stability ◽  
A Minor

© 2020 American Chemical Society. Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of ∼100 nm and a spacing of ∼50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 μm long was observed.

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