Sub-sized short bend beam configuration for the study of mixed-mode fracture

On the use of different diametral compression cracked disc shape specimens for introducing mode III deformation

“…The testing equipment and loading setup for conducting in-plane fracture tests (i.e., modes I and II) are relatively simple and such tests can be done by the conventional testing machines and common fixtures such as tensile/compression and three or four-point bend test setup. Accordingly, a number of test specimens including circular samples (Brazilian disc and flatten Brazilian disc under compression, [1][2][3][4][5][6][7][8][9][10] semi-circular bend, 6,[11][12][13][14][15][16][17] center crack ring under compression, [18][19][20][21] edge notch disc bend (ENDB), [22][23][24][25][26] and circular edge crack wedge loading 27 ), beam samples (three-point long beam, [28][29][30][31] three-point short beam, [32][33][34][35][36] and four-point bend beam [37][38][39][40][41][42][43][44] ), and thin plate shape samples (compact tension shear,…”

“…The testing equipment and loading setup for conducting in‐plane fracture tests (i.e., modes I and II) are relatively simple and such tests can be done by the conventional testing machines and common fixtures such as tensile/compression and three or four‐point bend test setup. Accordingly, a number of test specimens including circular samples (Brazilian disc and flatten Brazilian disc under compression, 1–10 semi‐circular bend, 6,11–17 center crack ring under compression, 18–21 edge notch disc bend (ENDB), 22–26 and circular edge crack wedge loading 27 ), beam samples (three‐point long beam, 28–31 three‐point short beam, 32–36 and four‐point bend beam 37–44 ), and thin plate shape samples (compact tension shear, 45–47 square plate in tension, 48,49 and triangular plate in bending 50–52 ) are among the frequently used test specimens employed in the past for mode I and mixed I/II fracture testing of different brittle and quasi brittle materials such as rock, geo‐materials, concrete, polymers, ceramics, and etc. However, for introducing out‐of‐plane or mode III deformation in a cracked specimen via a straightforward and direct manner, it is usually necessary to apply torsional‐type loads.…”

Experimental and theoretical framework for illustrating the dependency of fracture toughness with tensile, bending, and compression loading in asphaltic samples

“…For example, rectangular shape samples loaded either by tensile or bending loads are the most preferred fracture toughness testing methods for metals, composites, polymers, and ceramics. [1][2][3][4][5][6][7][8][9][10][11][12] This is mainly because the preparation, casting, cutting, and manufacturing of beam or plate shape samples is very easy for such materials and is more popular than the other test geometries. Accordingly, different test specimens including center or edge cracked plate loaded with far-field tension or bending, 13,14 notched rectangular beams subjected to three-or four-point bend loading, 15,16 double cantilever beam loaded by tension or bending, 17,18 and so forth have been employed earlier for the study of crack resistance in metals, composites, bone, ceramic, brittle polymers, and so forth.…”

Study on the global stress field of the rock mass under compression and shear considering three kinds of crack parameters

“…In addition, it is necessary to consider the effect of the non-singular term T-stress in Williams' expansion series of the stress field 43 at the crack tip. 14,19,44,45 Many researches show that the T-stress has a strong effect on the experiments, [46][47][48][49][50][51][52][53] such as positive T-stress can reduce the mixed mode I/II fracture toughness and can increase the fracture initiation direction. Opposite behavior can be seen where the Tstress is negative.…”