Structural compressive fatigue simulated via lattice discrete and microplane models

Accurate prediction of structural fatigue life under compression is crucial for infrastructure safety, yet the fatigue behavior of concrete remains insufficiently understood.This study proposes a dissipation hypothesis linking fatigue-induced degradation to cumulative inter-aggregate shear strain, leading to a pressure-sensitive interface model embedded in both discrete and microplane formulations.To validate this hypothesis, extensive experimental and numerical studies were conducted, including cylinder compression test of varying sizes, concrete mixes, and loading frequencies, alongside prestressed four-point bending tests representing structural compressive fatigue.Results indicate that direct transfer of fatigue data from cylinder tests to structural components is inadequate.Therefore, a detailed discrete mesoscale model of the prestressed four-point bending test was developed to further analyze and interpret structural fatigue damage.The mesoscale model, which uses a latticediscrete material idealization, is qualitatively compared with numerical studies performed using FE and the microplane model MS1.The studies include a comparison of the shape of hysteretic loops, stress redistribution along the cross-section, and the shape of energy dissipation profiles.