MICROMECHANICS-BASED FEM SIMULATION OF FIBER-REINFORCED CEMENTITIOUS COMPOSITE COMPONENTS

Fiber bridging along cracks is an important mechanism governing the fr acture toughness and the pseudo-ductility of fiber-reinforced brittle materials and structures. This paper attempts to predict structural be havior of fiber-reinforced cementitious composite (FRCC) components us ing the finite-element procedure with micromechanics-based constitutiv e modeling of the stress-displacement relation along the crack. The te nsile stress-displacement relation along a Mode I (opening) crack is e stablished based on fiber pullout curves derived from a micromechanica l model. A statistical model is used to account for random fiber distr ibution. Two-dimensional finite-element simulations of beam behavior a re performed with the finite-element package ADINA. Using the discrete crack approach, strain softening truss elements are placed along the crack to simulate the fiber bridging effect. Experiments of beams unde r four-point bending are performed with specimens containing different fiber volume fractions (up to 1.5%). The numerical results for the lo ad vs deformation behavior of the beams agree well with the experiment al results. The FEM procedure for micromechanics-based design and anal ysis of FRCC components is therefore established. Simulation of compon ent behavior to identify the most cost-effective design can, hence, be carried out. (C) 1997 Elsevier Science Ltd.