Non-local plasticity effects on notch fracture mechanics

Journal article

We investigate the influence of gradient-enhanced dislocation hardening on the mechanics of notch-induced failure. The role of geometrically necessary dislocations (GNDs) in enhancing cracking is assessed by means of a mechanism-based strain gradient plasticity theory. Both stationary and propagating cracks from notch-like defects are investigated through the finite element method. A cohesive zone formulation incorporating monotonic and cyclic damage contributions is employed to address both loading conditions. Computations are performed for a very wide range of length scale parameters and numerous geometries are addressed, covering the main types of notches. Results reveal a strong influence of the plastic strain gradients in all the scenarios considered. Transitional combinations of notch angle, radius and length scale parameter are identified that establish the regimes of GNDs-relevance, laying the foundations for the rational application of gradient plasticity models in damage assessment of notched components.

Authors: Martínez-Pañeda, E; del Busto, S; Betegón, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Theoretical and Applied Fracture Mechanics
• Volume: 92
• Pages: 276-287
• Publication date: 2017-09-28
• Acceptance date: 2017-09-20
• DOI: 10.1016/j.tafmec.2017.09.007
• EISSN: 1872-7638
• ISSN: 0167-8442
• Language: English
• Keywords: strain gradient plasticity; fatigue; finite element analysis; fracture; notch