Plastics and ebonite. Determination of indentation hardness by means of a a durometer (Shore hardness)

1992 ◽  
Keyword(s):  
Indentation Hardness ◽  
Shore Hardness

On the Relation between Indentation Hardness and Young's Modulus

1958 ◽  
Vol 31 (4) ◽  
pp. 896-906 ◽  
Author(s):  
A. N. Gent
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Empirical Relation ◽  
Rigid Sphere ◽  
Indentation Hardness ◽  
Shore Hardness ◽  
Theoretical Relation ◽  
Classical Elasticity ◽  
British Standard ◽  
Classical Elasticity Theory

Abstract A relation between British Standard and International rubber hardness and Young's modulus is derived from classical elasticity theory, and compared with the empirical relation given in B.S.903:1950. An experimental examination of the load-indentation relationship for a rigid sphere pressed into a flat rubber pad is described ; it indicates that the theoretical relation is more appropriate than the empirical one for small indentations, corresponding to hardnesses exceeding about 60° B.S. & I.R.H., and equally valid for hardnesses between about 40° and 60°. Moreover, the numerical constants are not subject to experimental uncertainty. If reduced major loads are stipulated for determining the hardness of rubbers of less than 35° to 40° B.S. & I.R.H., the theoretical relation should apply over the entire useful range. An approximate relation between Shore hardness and Young's modulus is derived similarly. The approximate equivalence of the British Standard and International rubber hardness and Shore hardness scales over the major part of the hardness range is confirmed.

Instrumented Indentation Test

2011 ◽  
pp. 167-233
Author(s):  
C. Ullner
Keyword(s):  
Indentation Test ◽  
Indentation Load ◽  
True Stress ◽  
Test Method ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Hardness Testing ◽  
Scope Of Application ◽  
Instrumented Indentation Test

Abstract Instrumented indentation hardness testing significantly expands on the capabilities of traditional hardness testing. It employs high-resolution instrumentation to continuously control and monitor the loads and displacements of an indenter as it is driven into and withdrawn from a material. The scope of application comprises displacements even smaller than 200 nm (nano range) and forces even up to 30 kN . Mechanical properties are derived from the indentation load-displacement data obtained in simple tests. The chapter presents the elements of contact mechanics that are important for the application of the instrumented indentation test. The test method according to the international standard (ISO 14577) is discussed, and this information is supplemented by information about the testing technique and some example applications. The chapter concludes with a discussion on the extensions of the standard that are expected in the future (estimation of the measurement uncertainty and procedures for the determination of true stress-strain curves).

Extended characterization of materials based on continuous instrumented indentation diagrams

2021 ◽  
Vol 2021 (3) ◽  
pp. 10-23
Author(s):  
B. A. Galanov ◽  
◽  
S. M. Ivanov ◽  
V. V. Kartuzov ◽  
◽  
...  
Keyword(s):  
Material Flow ◽  
Elastic Moduli ◽  
Contact Stiffness ◽  
Relative Size ◽  
Indentation Hardness ◽  
Instrumented Indentation ◽  
Characterization Of Materials ◽  
Instrumental Indentation

In addition to the traditional determination of hardness and elastic moduli from continuous diagrams of instrumental indentation, it is proposed to determine the yield stress, the characteristic of plasticity, the characteristic relative size of the elastoplastic zone under the indenter, and the volumetric deformation of the material in the area of contact of the indenter with the sample. The indentation diagram shows the transition point to the unconstrained material flow under the indenter. Keywords: indentation, hardness, elastic moduli, contact stiffness, elastic-plastic strains.

Determination of the Fatigue Resistance of Rubber Parts under Cyclic Shear Stress in Relation to Their Shape and Energy

1955 ◽  
Vol 28 (4) ◽  
pp. 1044-1053 ◽  
Author(s):  
Hermann Roelig ◽  
Guido Fromandi
Keyword(s):  
Vibration Isolation ◽  
Compression Modulus ◽  
Dynamic Tests ◽  
Shore Hardness ◽  
Cyclic Shear ◽  
Spring Suspension ◽  
Exact Design ◽  
Metal Bonds

Abstract Rubber is used far less frequently in tension than in compression for spring suspensions and vibration isolation. But for particularly soft springs, it is used in shear. For example, the compression modulus (at a deformation of 10 per cent of the height of the specimen) of a rubber cylinder 25 mm. in diameter and 25 mm. high, of 60° Shore hardness, may be 45 kg. per sq. cm., while its shearing modulus is only 7 kg. per sq. cm. Thus one may obtain a 6.5 times softer spring suspension by a shear mounting for the same volume of rubber. The use of rubber shear suspensions is facilitated by rubber-metal bonds, the quality of which today can be safely controlled technically in rubber factories. Thus we find shear suspensions in rubber-cushioned railway cars and automobile and aircraft construction. The exact design of such spring suspensions still is handicapped by lack of precise data on their fatigue strength, which can be obtained from dynamic tests. Such information would also facilitate the study of new elastomers and their comparison with those currently in use.

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