Failure Mechanics of Cohesive-Frictional Materials

摘要

Cohesive-frictional materials are known to exhibit strong coupling between thevolumetric and deviatoric behavior. The Reynolds effect is responsible for inelastic dilatancy which leads to localized failure modes which vary between tensile decohesion and mixed-mode shear-compression failure in simple shear and triaxial extension. In the course of this project analytical methods were developed to study the formation of discontinuous failure modes in softening and non-associated elastoplasticity. Quantitative localization results were obtained in order to assess the regularization properties of Cosserat continua which feature an internal length scale as compared to classical Boltzmann continua. The balance of angular momentum condition across internal discontinuities did suppress localization in micropolar materials except for mode I decohesion. This conversion of discontinuous failure modes was most notable when localization was studied computationally at the border between polar and non-polar behavior.