Anisotropic constitutive model of plasticity capable of accounting for details of meso-structure of two-phase composite material

Abstract

International audienceIn this work, we discuss a novel anisotropic constitutive model of plasticity, which can be used to replace the classical phenomenological models for composite materials, like concrete, with marked difference of behavior in tension and compression. The model is constructed from fine scales by making use of the corresponding meso-scale representation of concrete distinguishing aggregate from cement paste. The elastic response and failure mechanisms at this scale are represented by the corresponding unstructured mesh of truss elements, which is shown to be capable of representing a number of fine features of inelastic response, such as the statistical isotropy of elastic response placed in-between the stringent Hashin-Shtrikman bounds, the pronounced difference of behavior in tension and compression, the sensitivity of bi-axial compression strength to the volume fraction of aggregate and the bi-axial fracture energy corresponding to each particular mode of failure. The results of this kind obtained with meso-model are then packed within a new meso-scale model with these enhanced features, which can be used to successfully replace the standard phenomenological models of concrete in ultimate state computations of complex structures providing increased predictive capabilities

A concrete homogenisation technique at meso-scale level accounting for damaging behaviour of cement paste and aggregates

“…Similar techniques are used, among many others in [56,21,22,24-26, 28,69,6]. On the contrary, the introduction of a discontinuous kinematic field allows for the use of unaligned meshes, for instance following Strong Discontinuities approaches [27,9].…”

“…The constitutive law for a bond is assigned depending on the material represented by the sites [63,64,62,9,65]. Similarly a lattice network of particles connected by normal springs, shear springs or rotational spring can be considered [67,68].…”

“…The analyses performed in this paper relate to the meso-scale only, and are aimed to simulate the constitutive behaviour of the material, in order to evaluate the reliability and the limits of the method proposed, as done in [25,3,56,9]. The method will be presented and only the results of uniaxial compression processes will be reported in this work.…”

“…In the first case the boundaries of the discretised components coincide with material interfaces and no material discontinuity is present inside the finite elements [21][22][23][24][25][26]. In the second case, the unaligned mesh leads to material discontinuities inside the finite elements [27,9]. An Interface Transition Zone (ITZ) can also be introduced, for simulating the failure modes at the interface between the main phases [28,22,29].…”

“…A large number of scientific researches has been devoted to the numerical prediction of the mechanical properties of composite cementitious materials by means of meso-scale analysis [1][2][3][4][5][6][7][8][9][10][11]. Each component of the heterogeneous composite is individually modelled and, after assigning appropriate constitutive and kinematic models, the response of the composite can be simulated, including the evolution of the damaging process.…”