FRICTIONAL CRACK GROWTH INITIATION IN A NATURAL ORTHOTROPIC QUASI-BRITTLE SOLID

The frictional crack is extensively observed in natural phenomena like earthquake fracture, fracture at rock
fault line and in fracture of other geological materials. The contact between the flaw faces alters the stress
field in comparison to the stress field in an open condition or when not in contact. The crack growth
initiation in an open condition have been investigated sufficiently in literature. However, the frictional crack
or closed crack in an anisostropic medium has hardly been addressed. The naturally occurring biological
materials such as bone, wood, cartilage, etc. are anisotropic as well as quasi-brittle in nature. Considering
the vital application of these naturally occurring composites, it calls for a thorough investigation. The
current research work performs compression test on wood with an embedded central pore for different
contact surface conditions and orientation of pore. In addition to that, it carries out numerical simulation of
crack growth initiation and propagation using cohesive zone model (CZM) considering quasi-brittle nature
of wood. Further, it verifies the applicability of classical fracture criteria for friction crack propagation in
wood.
EXTENDED ABSTRACT