Event-based lattice modeling of strain-hardening cementitious composites

This paper presents novel developments in the lattice modeling of fiber reinforced cement composites, in which the individual fibers are explicitly represented. Attention is given to the modeling of strain-hardening cement composites under tensile loading. The pullout forces of fibers are derived from micromechanical bases and distributed along the fiber embedment lengths. This spatial description of the fiber bridging forces provides realistic representations of stress transfer between the fiber and matrix, which is essential for simulating crack openings and crack spacing. Stress transfer is modified to account for multiple cracks intersecting individual fibers, which is typical for materials with closely spaced cracks. Multiple cracking generates islands of material interconnected by fiber bridges, which places extraordinary demands on the solution procedure. An event-by-event solution strategy is developed for this reason. Comparisons with test results demonstrate the model's ability to simulate global and crack-local features. In particular, simulated histograms of crack opening displacement compare favorably with those measured experimentally.