Mechanism of in-plane fracture growth in particulate materials based on relative particle rotations
In-plane fracture propagation in particulate materials (rock,concrete) under high tri-axial compression is observed in both Mode I tensile cracks (opened by additional load),Mode Ⅱ shear cracks and in Mode I anti-cracks (compaction bands).This commonality suggests that when the conventional fracture mechanisms are supressed by high compression,a new universal mechanism takes over.We propose a fracture growth mechanism based on mutual rotations of the particles leading to breakage of inter-particle bonds followed by particle detachment and re-compaction.The Cosserat characteristic lengths are found to be of the order of the particle size.This allows expressing the stress concentrations as an intermediate asymptotics (between the Cosserat continuum characteristic length and the crack length).For Mode I crack and anti-crack and for Mode Ⅱ crack the stress singularities are the same as for the cracks in a classical continuum,while the moment stress has a stronger singularity (3/2 power).This stress singularity leads to relative particle rotations and bending of interparticle bonds.The tensile microstress induced by the bending is an order of magnitude higher than the stress associated with conventional stress singularities.
Fracture Criterion Grain rotation Moment stress Small-scale Cosserat continuum Compaction band
Arcady V. Dyskin Elena Pasternak
Deep Exploration Technologies Cooperative Research Centre,School of Civil and Resource Engineering,U Deep Exploration Technologies Cooperative Research Centre,School of Mechanical and Chemical Engineer
国际会议
北京
英文
1-10
2013-06-16（万方平台首次上网日期，不代表论文的发表时间）