Microplane fatigue model MS1 for plain concrete under compression with damage evolution driven by cumulative inelastic shear strain

Abstract

Mathematical modeling of fatigue behavior of concrete under compressive loading presents a challenging topic that attracts an increasing interest of the scientific community. The present paper proposes a new formulation of the microplane model referred to as MS1 aiming to capture the fundamental inelastic mechanisms that can reflect the tri-axial stress redistribution within a material zone upon cyclic loading at subcritical load levels. The key idea of the proposed approach is to link the fatigue damage evolution to the cumulative inelastic shear strain. In this way the accumulation of fatigue damage under compressive loading owing to internal shear/sliding between aggregates at subcritical load levels can be reflected. The present model is developed within the context of the microplane theory using a homogenization scheme based on the principle of energy equivalence with a direct tensorial representation of the effective elastic stiffness. The paper presents elementary studies of the model behavior accompanied with the evaluation of its capability to capture the response of concrete fatigue under compressive loading. A calibration and validation procedure of the model response is provided based on an accompanying experimental program including normal- and high-strength concretes subjected to several loading scenarios. The model shows the ability to reproduce the concrete behavior under monotonic, cyclic and fatigue loading with consistent set of material parameters.