TY - JOUR

T1 - The elastic distortion problem with large rotation in discontinuous deformation analysis

AU - Wu, Jian Hong

N1 - Funding Information:
The author appreciates the valuable suggestions from the reviewers to improve this paper. In addition, the author wants to specially thank the Ministry of Science and Technology of Taiwan (Project No. 102-2221-E-006-197-MY3 ) for the financial support of a part of the paper publications.
Publisher Copyright:
© 2015 Elsevier Ltd.

PY - 2015/9/1

Y1 - 2015/9/1

N2 - Conventional discontinuous deformation analysis (DDA) results in a change of block volume, which is known as free expansion, during rotation calculations because of the use of a linear displacement function to simulate the behavior of a block with a rigid body and elastic behaviors. This study demonstrates that the linear displacement function also generates unsolved elastic distortion, especially when the block undergoes large rotation in each calculation step. The distortion disturbs the contact judgment in the open-close iteration and update calculations of vertex coordinates, stresses, velocities, etc. at the end of each calculation step. A new procedure follows the flow chart of the original DDA, but it adopts additional codes for the coordinate-transformation calculations in vertex coordinate, stress, and velocity updates. When the vertex coordinates are updated, vertex displacements caused by strains are calculated before involving the block-rotation term in the displacement function to mitigate the elastic distortion. In addition, new codes compile formulas to transform stresses and velocities with block rotation. The new DDA ensures the correctness of rotating elastic calculations to solve practical falling rock problems with a large rotational angle in each calculation step.

AB - Conventional discontinuous deformation analysis (DDA) results in a change of block volume, which is known as free expansion, during rotation calculations because of the use of a linear displacement function to simulate the behavior of a block with a rigid body and elastic behaviors. This study demonstrates that the linear displacement function also generates unsolved elastic distortion, especially when the block undergoes large rotation in each calculation step. The distortion disturbs the contact judgment in the open-close iteration and update calculations of vertex coordinates, stresses, velocities, etc. at the end of each calculation step. A new procedure follows the flow chart of the original DDA, but it adopts additional codes for the coordinate-transformation calculations in vertex coordinate, stress, and velocity updates. When the vertex coordinates are updated, vertex displacements caused by strains are calculated before involving the block-rotation term in the displacement function to mitigate the elastic distortion. In addition, new codes compile formulas to transform stresses and velocities with block rotation. The new DDA ensures the correctness of rotating elastic calculations to solve practical falling rock problems with a large rotational angle in each calculation step.

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U2 - 10.1016/j.compgeo.2015.06.001

DO - 10.1016/j.compgeo.2015.06.001

M3 - Article

AN - SCOPUS:84934953537

VL - 69

SP - 352

EP - 364

JO - Computers and Geotechnics

JF - Computers and Geotechnics

SN - 0266-352X

ER -