关键词: Cosserat扩展模型, 弯曲变形, Mohr-Coulomb准则, Drucker-Prager准则, MATLAB, 弹塑性有限元

Abstract: The FEM programs of Cosserat expanded constitutive model are written by all use of the Mohr-Coulomb criterion at present. However, the Mohr-Coulomb yield surface is not smooth because of the hexagonal corners. These corners of the hexagon can cause numerical difficulty in its application to plasticity theory. The Drucker-Prager criterion can be viewed as a smooth approximation to the Mohr-Coulomb criterion to avoid such difficulty, which may be made to match the Mohr-Coulomb criterion by adjusting the size of the cone. So, there is an urgent need for extending the Cosserat theory based on Drucker-Prager criterion. Based on the above two criteria, the elastoplastic FEM programs for Cosserat expanded constitutive model are written and applied to flexural deformation analysis of the underground cave in the interbedded rock mass by using MATLAB. The analytical results show that the program is effective in analyzing the flexural deformation of underground cave in the interbedded rock mass. Most importantly, the Drucker-Prager criterion-based FEM program is observed to have a higher convergence speed and stability.

Key words: Cosserat expanded constitutive model, flexural deformation, Mohr-Coulomb criterion, Drucker-Prager criterion, MATLAB, elastoplastic FEM