R-curve behavior and roughness development of fracture surfaces

摘要: We investigate the idea that fractal geometry of fracture surfaces in quasibrittle materials such as concrete, rock, wood and various composites can be linked to toughening mechanisms. Recently, complete scaling analysis has shown anisotropy crack developments longitudinal transverse directions. The anomalous law needed describe accurately these particular emphasizes insufficiency dimension, usually used characterize morphology surfaces. It is a surface initiating from straight notch, exhibits first region where amplitude roughness increases function distance second one saturates at value depending on specimen size. Such related an R-curve behavior zone develops. post regime, associated with saturation roughness, characterized by propagation constant resistance. Moreover, we show main consequence this connection between roughening microscale characteristics macroscale material-dependent relative critical energy release rate. These results are confirmed experiments Wood (Spruce Pine).