Abstract
As for the JIS rubber hardness tester, the thickness of a testpiece is indicated to be not less than 12mm. Also it is indicated that, if the testpiece is thin, it needs to be piled up till the total thickness exceeds 12mm.
The JIS hardness tester is convenient, when it is used as a means of quality control. But the JIS hardness is not strictly based upon the theory of physics. Therefore, the authors have ever proposed the use of shear modulus G, instead of hardness.
Here it was examined whether the indications for the JIS hardness can be applied to the calculation of G. Experiments showed that the thickness of 12mm is, in some sense, appropriate, but the piling of test-pieces is not adequate. The value of G of piled-up testpieces is less than that of single specimen which has the same thickness as the former.
