Ratio of Crack Opening Dependency

ANALYSIS OF MECHANICAL AND HYDRAULIC PROPERTIES OF CRACKED STRUCTURE BY THE RATIO OF CRACK OPENING DEPENDENCY (RCOD)... 

Abstract The Ratio of Crack Opening Dependency (RCOD) was proposed as a new index to simultaneously evaluate the mechanical and hydraulic properties of cracked structure which contains many open cracks within. The RCOD is an index which is defined as the ratio of total amount of crack opening and the total deformation of cracked structure. The efficiency of RCOD as an index to evaluate the coupled problem was numerically analyzed by applying SCDDM (stress compensation-displacement discontinuity method) to the two dimensional multi crack model. It was shown that RCOD is an useful index which can directly evaluate the deformability and the permeability of the cracked structure without any parameters such as stresses or crack size. The possibility of application of RCOD to the field measurements was also discussed. 

Let us introduce the RCOD (ratio of crack opening dependency) R as a new index to evaluate the cracked structure. The RCOD is defined by the ratio between the total strain and crack opening strain, and given by the following equation. 

The CTH approach is able to control the crack width, which can be closed by controlling the compression pre-strain level. A simple equation has been established by Li et al. [54] to correlate the crack width to be closed and the pre-strain level during compression programming. Cracks with different opening widths can be closed based on the level of compression programming (of course it is limited by the maximum allowed compression pre-strain level). In the unconstrained shape recovery approach such as the SMASH approach, it has not been demonstrated that it can close a wide-opened crack with constrained boundary. Also, it cannot control the crack width that can be closed because it depends on the external load to perform programming and relies on the shape recovery ratio and boundary condition of specimens to perform crack closing. 

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