Scaling of quasi-brittle fracture: Boundary and size effect

• Published in: Mechanics of materials Vol. 38; no. 1; pp. 128 - 141
• Main Authors: Duan, Kai, Hu, Xiaozhi, Wittmann, Folker H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier Ltd 2006; Amsterdam Elsevier Science; New York, NY
• Subjects: Boundary effect; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fracture process zone; Fracture toughness; Fundamental areas of phenomenology (including applications); Physics; Quasi-brittle fracture; Size effect; Solid mechanics; Static elasticity (thermoelasticity...); Strength; Structural and continuum mechanics; Fracture process zone; Quasi-brittle fracture; Boundary effect; Strength; Size effect; Fracture toughness; Measurement; Model following; Brittle fracture; Fracture criterion; Modeling; Plate; Short crack; Edge effect; Crack length; Scaling; Crack tip; Asymptotic approximation; Rupture strength
• ISSN: 0167-6636; 1872-7743
• DOI: 10.1016/j.mechmat.2005.05.016

A boundary effect model recently developed for scaling of quasi-brittle fracture is used to study the common size effect on strength and fracture toughness of finite-sized specimens. An equivalent crack length is adopted following the boundary effect model and used to measure the distance of a crack tip to the front and back specimen boundaries. This equivalent crack leads to a simplified asymptotic solution for finite-sized specimens akin to that for a large plate with a small edge crack. The two common failure criteria, the strength and the linear elastic fracture mechanics (LEFM) K IC criteria, are taken as two asymptotic limits. The transition from the strength to toughness criterion is then given by the asymptotic solution. The recent asymptotic model for finite-sized specimens/structures is applied to geometrically similar specimens of a fixed α-ratio, and specimens of identical size, but different α-ratios.