Micro-mechanics and continuum damage mechanics

Abstract

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A simple damage model for concrete considering irreversible mode‐II microcracks

“…1,2,17,18 However, there is another type of crack on the wall of the micro-defects and mode-I crack: the mode-II microcracks (parallel to the axial loading in uniaxial loading case), which has not been well considered in concrete models in present literature as mentioned before. [11][12][13][14][15][16][28][29][30][31][32][33][34][35][36] The literature based on experimental observations, atomic simulations and mechanical analysis validated that the real crack is blunt, resulted from the local shear stresses (i.e. sufficient high gradient of stress σ v in Figs 1c & 2a) on the crack wall and surroundings.…”

“…However, this damage behaviour is not well considered in most present literature concerning the irreversible strains in concrete. In detail, initially, the micromechanics method [28][29][30][31][32][33][34][35][36] proposed that the irreversible strains are produced by a series of cracking, which are distinguished as follows: the irreversible opening of mode-I crack due to locking mechanisms of crack faces 28 ; the irreversible sliding-like of mode-II crack (not mode-II microcracks) due to toughness of crack faces 29,30 ; the irreversible-frictional sliding over crack surface 31,32 ; the irreversible cracking of fracture process zone 33,34 ; and other cracking mechanisms. 35,36 Additionally, the macro-mechanics method [11][12][13][14][15][16] generally considered rarely the comprehensive mechanism of concrete damage, because it usually focused on the accurate characterizing of the macroscopic mechanical behaviours.…”

“…The work develops the mentioned contributions [11][12][13][14][15][16][28][29][30][31][32][33][34][35][36] in two aspects, the micromechanical description of mode-II microcracks and the thermodynamics-based modelling of damage behaviours in concrete.…”

On the dynamic fragmentation of two limestones using edge-on impact tests

“…To account for sliding cracks, i.e., when compressive stresses are dominating such as in zones close to the impact point, the overall material behavior is described by plasticity-like models [40][41][42]. In the present case, it is proposed to use the simplest of them, namely, perfect plasticity.…”

Local Approach of Fracture Based on Continuum Damage Mechanics and the Related Problems

“…Recent development of continuum damage mechanics (CDM) has provided an important framework for the failure analyses of components in engineering structures [1][2][3][4][5][6][7][8][9]. By use of the proper constitutive and evolution equations taking account of material damage, CDM is capable of describing the whole process of failures ranging from damage development, crack initiation, crack (or failure zone) growth to final fracture.…”