Experimental determination of the critical COD of rock-like materials using Digital Image Correlation

摘要

Crack Opening Displacement (COD) is a convenient tool for the quantification of the capacity of materials containing crack-like defects to deform before crack extension. In addition its critical value (i.e. its value at the crack initiation moment) is often used as a 'geometric' fracture criterion. In spite of some doubts regarding its natural foundation COD is an irreplaceable tool especially for in-situ applications. In this context the COD is determined here experimentally for rock-like materials in an effort to determine the load-COD relation and to explore the dependence of the critical COD on the dimensions of the notch with respect to the size of the specimens used.