Abstract
AbstractA micromechanical distinct element method (DEM) model is adopted to analyze the grain‐scale mechanism that leads to the brittle‐ductile transition in cohesive‐frictional materials. The cohesive‐frictional materials are idealized as particulate assemblies of circular disks. While the frictional sliding of disks is sensitive to the normal compressive stress exerted on contacts, normal force can be both caused by interpenetration and long‐range cohesive bonding between two particles. Our numerical simulations indicate that the proposed DEM model is able to replicate the gradual shift of porosity change from dilation to compaction and failure pattern from localized failures to cataclastic flow upon rising confining pressure in 2‐D biaxial tests. More importantly, the micropolar effect is examined by tracking couple stress and microcrack initiation to interpret the transition mechanism. Numerical results indicate that the first invariant of the couple stress remains small for specimen sheared under low confining pressure but increases rapidly when subjected to higher confining pressure. The micropolar responses inferred from DEM simulations reveal that microcracking may occur in a more diffuse and stable manner when the first invariant of the macroscopic couple stress are of higher magnitudes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.