ACCURATE COMPARATIVE DETERMINATION OF THE INPLANE SHEAR MODULUS OF T300/914 BY THE IOSIPESCU AND 45-DEGREES OFF-AXIS TESTS

This paper compares the initial shear modulus distributions obtained from [0](20), [90](20) and [0/90](5s) losipescu and [45](20) off-axis T300/914 specimens. The data reduction processes for the two tests are presented together with a finite element analysis of the losipescu test that enables the determination of correction factors to account for the non-homogeneity of the stress and strain fields along the notch line. A preliminary 45 degrees off-axis test is performed to determine a region of linear elastic behaviour within which the samples are each tested four times. Close examination of the test data leads to a detailed discussion of the quality of the losipescu specimens in terms of perpendicularity of the loading surfaces to the lateral faces. The degrees of scatter due to the mechanical loading conditions and to the sample to sample variations are compared.