Accurateprediction 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…
Accurateprediction 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 formu- lations. To validate this hypothesis, extensive experimental and numerical studies were conducted, including cylinder compression test of varying sizes, concrete mixes, and loading frequencies, along- side 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. There- fore, 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 lattice- discrete 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.