Three point bending tests were conducted with acoustic emission (AE) monitoring on specimens with and without notches of two different sizes. To investigate mixed mode fracture, beam tests with off-center notches were studied as well. The experiments indicated that around peak stress, the AE localized to form an intrinsic process zone. The discrete element technique was used to mimic fracture in bending. The numerical model was made of rigid circular particles that interact through normal and shear springs. These particles were glued to each other using normal and shear bonds. A microcrack formed in tension or shear was simulated by breakage of the bond between two particles in contact. The simulated material was calibrated for elastic properties, unconfined compressive strength and bending tensile strength. In the model, slightly overlapped particles were used to obtain a more realistic ratio of compressive to tensile strength. The beam strength with and without notches and the fracture path were studied in the numerical experiments. Two models for normal bond failure were considered, namely an instantaneous normal bond breakage and normal breakage with softening models. The numerical results obtained were compared with those from laboratory experiments.
|Original language||English (US)|
|Title of host publication||American Rock Mechanics Association - 40th US Rock Mechanics Symposium, ALASKA ROCKS 2005|
|Subtitle of host publication||Rock Mechanics for Energy, Mineral and Infrastructure Development in the Northern Regions|
|Publisher||American Rock Mechanics Association (ARMA)|
|State||Published - 2005|
|Event||40th US Rock Mechanics Symposium: Rock Mechanics for Energy, Mineral and Infrastructure Development in the Northern Regions, ALASKA ROCKS 2005 - Anchorage, United States|
Duration: Jun 25 2005 → Jun 29 2005
|Name||American Rock Mechanics Association - 40th US Rock Mechanics Symposium, ALASKA ROCKS 2005: Rock Mechanics for Energy, Mineral and Infrastructure Development in the Northern Regions|
|Other||40th US Rock Mechanics Symposium: Rock Mechanics for Energy, Mineral and Infrastructure Development in the Northern Regions, ALASKA ROCKS 2005|
|Period||6/25/05 → 6/29/05|
Bibliographical noteFunding Information:
ACKNOWLEDGEMENTS: Partial support was provided by NSF grant number CMS-0070062.
Copyright 2005, ARMA, American Rock Mechanics Association.