Side-groove effects in three-dimensional small-scale yielding: A load and thickness-scaling model

• Published in: Engineering fracture mechanics 2013-04, Vol.102, p.218-234
• Main Authors: Sobotka, J.C., Dodds, R.H.
• Format: Article
• Language: English
• Subjects: 3D thickness scaling; Boundaries; Cleavage; Cleavage failure; Ductile-to-brittle transition; Ferritic stainless steels; Fracture mechanics; Mathematical models; Self-similarity; Side grooves; Steels; Three dimensional; Three-dimensional effects; Weibull stress
• ISSN: 0013-7944; 1873-7315
• DOI: 10.1016/j.engfracmech.2013.02.016

► Employs extraordinarily refined 3D models to compute high-fidelity deformations in the crack-front region. ► Reveals an improved, quantitative understanding of side-groove effects. ► K-bar scaling (K-bar=K/(yield stress*sqrt[B]) in 3D SSY fields is shown to also hold for side-grooved specimens. ► Weibull stress values exhibit K-bar scaling. ► A new non-dimensional parameter is introduced to describe this outcome. ► Probabilities of fracture are compared for plane-strain, 3D plane-sided and 3D side-grooved configurations. This study investigates the influence of side grooves on near-front fields that drive cleavage fracture processes in ferritic steels under 3D small-scale yielding conditions. High-fidelity, finite-strain analyses of boundary-layer models for initially straight crack fronts provide elastic–plastic fields. Numerical solutions demonstrate that non-dimensional, self-similar scaling of crack-front fields for plane-sided specimens also holds for the side-grooved configurations. Furthermore, Weibull stress values exhibit a non-dimensional, thickness scaling controlled by a single non-dimensional parameter. This thickness scaling holds for low-to-high hardening rates typical of ferritic steels under imposed loading levels that range in a 3D setting from near plane-strain to near plane-stress conditions.