Concrete Stress Intensity Factor Evaluation With a Digital Image Correlation Approach

摘要

A method for determining mode Ⅰ and mixed-mode Ⅰ-Ⅱ stress intensity factors of concrete material was developed in this research on the basis of the displacement fields obtained through a digital image correlation (DIC) approach. Single-edge notched (SEN) concrete beams subjected to three points bending and four points shearing exertions were implemented for conducting the experiments to evaluate the mode Ⅰ and mixed-mode Ⅰ-Ⅱ fracture propagations. The dynamically varying displacement fields around the crack tip are determined by the DIC approach corresponding to the crack propagation. The instant positions of the crack tip and the corresponding stress intensity factors were determined with utilization of the displacement fields around the crack tip. The results of the research showed that the mode Ⅰ and mixed-mode Ⅰ-Ⅱ stress intensity factors and crack tip positions of concrete materials can be accurately and effectively determined with the method developed. More significantly, the displacement field and the fracture parameters of the concert material can all be quantitatively determined for any instance corresponding to the processes of the crack propagations.