On the energy dissipation in confined concrete subjected to shear cyclic loading

Abstract

The establishment of a simple engineering rule for predicting the fatigue failure of concrete has been pursued over the past decades. An energetic approach to the matter seems to be an attractive option that many researchers have embraced. In the present work, the authors attempt to contribute to the establishment of such a rule. In particular, the energy dissipation of confined concrete subjected to shear cyclic loading is studied and quantified. For this purpose, a microplane fatigue model recently introduced by the authors, referred to as MS1, is used. It aims to capture the fundamental inelastic mechanisms driving the tri-axial stress redistribution within a material zone during the fatigue damage process in concrete. To this end, the fatigue damage evolution is linked to a measure of cumulative inelastic shear strain at the microplane level, reflecting the accumulation of fatigue damage due to internal shear/sliding between aggregates at subcritical pulsating load levels. To isolate the dissipative mechanism mentioned above, test configurations with dominant shear stress seem to be more appropriate. In the present work, a punch-through shear test (PTST) FE model is used to induce shear-dominated stresses and strains along the ligament of a specimen. Numerical studies are first presented to evaluate the behavior and energy dissipation at the elemental interface level. The interface is introduced in the MS1 microplane material model, which is capable of reproducing the concrete behavior under monotonic, cyclic, and fatigue loading with consistent set of material parameters. Quantification of the energy dissipation for each introduced dissipative mechanism is performed at each microplane and integrated via a well-established homogenization scheme to evaluate the macroscopic energy dissipation. Later, an analysis of the energy dissipation of the PTST process zone is performed for cyclic loading under two different subcritical cyclic load amplitudes.

Fatigue-Induced Concrete Fracture Under Combined Compression And Shear Studied Using Standard Cylinder And Refined Punch-Through Shear Test Setup

“…It can be observed that there is a clear increment of the plastic energy dissipation, while the damage energy dissi- pation remains in comparison of the same order. Numerical studies previously presented by the authors in [12,13] consistently yield similar results, where the energy dissipation attributed to damage does not change as dramatically as the plastic energy dissipation for simulations of the same test setup under the same boundary conditions.…”

“…by replacing ψN , utilizing the chain rule, operating as described in [12,13], and integrating the dissipation rates with respect to the pseudo time t, the resulting expression yields the total energy dissipation associated with a microplane in the normal direction:…”

Phase-Field Modeling of Fatigue Crack Propagation in Brittle Materials

“…It should be noted that such limitations of the current formulations of the PF-CZM can be improved by incorporating plasticity with kinematic hardening and considering a different fatigue hypothesis that links the dissipative processes of damage and plasticity, as shown in [33,34,107,108]. That enables the accumulation of the plastic strains under constant amplitude cyclic loading, which is known as the ratcheting mechanism.…”