A brittle aggregate composite such as portland cement concrete or mortar is modeled in two dimensions as a system of perfectly rigid particles of various sizes separated by interface layers that are characterized by a given force-displacement relation for the normal and tangential components. The force-displacement relation exhibits for the normal component a tensile strength limit followed by a sudden drop of force to zero. The system of rigid particles is generated randomly. The particles are not allowed to overlap and are generally not in contact; however, when the distance between the particles is less than a certain limit, a deformable interface layer is introduced. Numerical simulation of a fracture specimen with a notch shows that the fracture front consists of an irregular band of interparticle cracks the width of which is about three maximum particle sizes. The interparticle cracks remain continuous and do not coalesce into a continuous line fracture until the deformation is very large. The load-displacement relation exhibits gradual softening after the peak force, with a rapid force decrease followed by a long tail of slowly decreasing force. These features qualitatively agree with observations of concrete.
|Original language||English (US)|
|Number of pages||12|
|Journal||Journal of Engineering Mechanics|
|State||Published - Nov 1987|
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering