Understanding Brittle Compressive Fracture in Single and Multi-Void Systems via Linear Elastic Stress Fields

Determining compressive fracture behaviour via fundamental fracture mechanics has proven difficult due to analytical complexities. However, recent studies have yielded significant breakthroughs. Linear elastic (LE) K_I variation with crack length in uniaxial compression has been found for certain void geometries—the observed K_I nonlinearity may independently explain stable compressive crack propagation, a long-outstanding issue. Other authors have also noted that LE stress fields of continua with voids in uniaxial compression have predictive value in crack propagation, but detailed guidelines for stress field interpretations have not yet been proposed. Together, these findings suggest an accurate interpretation of LE stress field components in a fracture context may be a significant step towards describing compressive fracture. Herein, concepts which may prove useful in the interpretation of LE stress fields are proposed. Chief among these concepts is the small flaw geometry assumption, a concept inherent in stress concentration studies that permits the computation of stress intensity factors from LE stress fields. The presented concepts are used to comment on the fracture characteristics of single and multi-void systems. These concepts are also used to provide guidance on determining the zone of influence (ZOI) of a void subjected to a particular distant loading.