Incorporating size effect into a micromechanical model for brittle materials

• Main Author: Roush, Wm. Patrick
• Format: Text
• Language: unknown
• Published: LOUIS 2014
• Subjects: Deformations (Mechanics); Ceramic materials > Mechanical properties; Ceramic materials > Design and construction; Plasticity; Sea ice
• Online Access: https://louis.uah.edu/uah-theses/84; https://louis.uah.edu/context/uah-theses/article/1083/viewcontent/roush_10120.pdf

This research addresses computational modeling of the size effect in brittle materials, a phenomenon commonly seen in laboratory tests but has not been adequately accounted for in computational models for such materials. Size effect is accounted for in this research by extending a damage model for brittle materials (the DCA model), which is based on the consideration of micromechanics of defects in the materials. In particular, the statistical distribution of the defects in a brittle material is assumed to vary with the size of the material sample under consideration. The idea has been numerically implemented in the DCA model and applied to sea ice, a quasi-brittle material of considerable importance for many applications (e.g., design of offshore structures). The numerical results of the size effect in sea ice are presented and compared with the results given by an empirical model (ISO-19906), which has been widely used in the design of offshore structures. Comparisons show that the size effect predicted by the extended model agrees well with that given by ISO-19906. As the model is based on the micromechanics of material defects, results of this research provide a mechanics basis for ISO-19906, which is purely empirical.