Development of Micro-Macro Continuum-Discontinuum Coupled Numerical Method
A micro-macro and continuum-discontinuum coupled model and corresponding computer codes are developed in this thesis for rock dynamics study. Firstly, a new micromechanical model for describing the elastic continuum based on the underlying microstructure of material is proposed. The model provides a more general description of material than linear elasticity. Then, a numerical model Distinct Lattice Spring Model (DLSM) is developed based on the RMIB theory. The new proposed model has the advantages of being meshless, and automatic continuum description through underlying discontinuum structure and directly using macroscopic elastic parameters. Following this, the multi-scale DLSM (m-DLSM) is proposed to combine DLSM and NMM. The proposed model uses a tri-layer structure and the macro model can be automatically released into micro model during calculation. Forth ward, the ability of DLSM on modeling dynamic failure is studied. A damage based micro constitutive law is developed. Relationships between the micro constitutive parameters and the macro mechanical parameters of material are provided. The micro parameters can directly be obtained from macro experimental results, i.e., tensile strength and fracture energy, through these equations. Moreover, the ability of DLSM on modeling wave propagation is enhanced and verified. Non-reflection boundary condition and methods to represent discontinuity in DLSM are developed. Finally, the parallelization of DLSM and 2D implicit DLSM are introduced. The main achievements of the whole PhD work and future research works are summarized and prospected in the conclusion part of the thesis.
Keywords: rock dynamics ; numerical model ; microstructure ; RMIB ; DLSM ; m-DLSM ; NMM ; multi-scale ; dynamic failure ; wave propagation ; Open MP ; MPI ; parallelization ; implicit ; MLS ; dynamique des roches ; modèle numérique ; microstructure ; RMIB ; DLSM ; m-DLSM ; NMM ; multi-échelle ; rupture dynamique ; propagation des ondes ; Open MP ; MPI ; parallélisation ; implicite ; MLSThèse École polytechnique fédérale de Lausanne EPFL, n° 4807 (2010)
Programme doctoral Mécanique
Faculté de l'environnement naturel, architectural et construit
Institut d'ingénierie civile
Laboratoire de mécanique des roches
Record created on 2010-07-15, modified on 2016-08-08