OS15-3-4 Improved Rail Shear Method of ASTM D4255/D4255M for Cyclic Shear Tests of Fibrous Composites

Abstract

This paper presents an improved rail shear method of ASTM D 4255/D4255M and the design procedure of new fixture for low cyclic shear loading. This fixture is designated to determine mechanical properties of in-plane shear modulus, nonlinear shear stress-strain curves, shear strength and visco-elastoplastic behaviour of fibrous composites under cyclic shear loads. A series of experiments have been carried out using the new rig to determine shear stress-strain response of unidirectional fibre reinforced laminated specimens under various cyclic loading conditions. An FE simulation has been conducted using a commercial code ABAQUS and its user subroutine UMAT to define nonlinear material behaviour as a verification of the accuracy of the new Cyclic Rail Shear Fixture (CRSF).

On the optimal choice of fibre orientation angle in off-axis tensile test using oblique end-tabs: Theoretical and experimental studies

“…Shear characterization of unidirectional layers for composite materials continues being a not fully solved problem. In the last fifty years many different approaches have been proposed to solve this problem (rail shear test [1][2][3][4][5][6][7], thin-walled tube torsion test [8,9], off-axis tensile test [10][11][12][13][14][15][16][17][18][19][20][21][22], ±45º tensile test [23][24][25][26], Arcan test [27][28][29][30], Iosipescu test [31][32][33], asymmetric four-point bend test [34,35], plate twist test [36,37], v-notched rail shear test [38][39][40], off-axis flexural test [41][42][43] and shear frame test [44]), although anyone of these approaches has achieved an unquestionable support. In general, a characterization test must be as simple as a tensile test, and mainly for this reason, the most successful approach for shear characterization has been the ±4...…”