Simulation of dynamic behavior of quasi-brittle materials with new rate dependent damage model

Abstract

Abstract. In concrete often complex fracture and fragmentation patterns develop when subjected to high straining loads. The proper simulation of the dynamic cracking process in concrete is crucial for good predictions of the residual bearing capacity of structures in the risk of being exposed to extraordinary events like explosions, high velocity impacts or earthquakes.As it is well known, concrete is a highly rate dependent material. Experimental and numerical studies indicate that the evolution of damage is governed by complex phenomena taking place simultaneously at different material scales, i.e. micro, meso and macro-scales. Therefore, the constitutive law, and its rate dependency, must be adjusted to the level of representation. For a proper phenomenological (macroscopic) representation of the reality, the constitutive law has to explicitly describe all phenomena taking place at the lower material scales. Macro-scale inertia effects are implicitly simulated by the equation of motion.In the current paper, dynamic crack propagation and branching is studied with a new rate-dependent stress-based nonlocal damage model. The definition of rate in the constitutive law is changed to account for the inherent meso-scale structural inertia effects. This is accomplished by a new concept of effective rate which governs the dynamic delayed response of the material to variations of the deformation (strain) rate, usually described as micro-inertia effects. The proposed model realistically simulates dynamic crack propagation and crack branching phenomena in concrete.

Development of a dataset on the in-plane experimental response of URM piers with bricks and blocks

“…A modified Drucker-Prager damage loading surface is adopted in the model like in [2,18]. Two equivalent strain functions for compression crushing (ε eqc ) and tensile cracking (ε eqt ) are expressed as a combination of the first (I ε ) and second deviatoric (J ε d ) invariants of strain [34]. In eq.…”

“…Where r is derived from the triaxiality factor proposed by Lee and Fenves [37] for multiaxial loading states, α is a constant set to 0.1 as in [2] and the mechanical parameters k 0t and k 0c are the damage initiation strains in tension and compression [34].…”

Prediction of Elastic Parameters of Particle Reinforced Composites Using Finite Element Simulations

“…The best-fitted region corresponds to the region where no damage occurs in the material, i.e., before the Young modulus decreases. A nonlinear interface and matrix behavior must be incorporated into the numerical model to capture this damaging process, such as proposed in the literature [10][11][12][13][14] . The identification of model parameters of further models is complex and, generally, involves indirect measurements.…”

“…However, phenomena such as debonding and crack propagation are very non-linear, making their modeling more complex. Therefore, many researchers dedicate themselves to simulating the damage [10][11][12] , phase debonding 13,14 and plasticity 15,16 . In particular, some of them [12][13][14] take into account the nonlinear phenomena in the homogenization process.…”

Dynamic simulations of traditional masonry materials at different loading rates using an enriched damage delay: Theory and practical applications

“…Where r is derived from the triaxiality factor proposed by Lee and Fenves [22] for multiaxial loading states, α is a constant set to 0.1 as in [5] and the mechanical parameters k 0t and k 0c are the damage initiation strains in tension and compression [23]. Two damage evolutions laws called for compression and tension are dependent on the damage initiation strains determined by the stress state of the integration point.…”