Numerical modelling of intergranular fracture in polycrystalline materials and grain size effects
Journal Title: Frattura ed Integrità Strutturale - Year 2011, Vol 5, Issue 17
Abstract
In this paper, the phenomenon of intergranular fracture in polycrystalline materials is investigated using a nonlinear fracture mechanics approach. The nonlocal cohesive zone model (CZM) for finite thickness interfaces recently proposed by the present authors is used to describe the phenomenon of grain boundary separation. From the modelling point of view, considering the dependency of the grain boundary thickness on the grain size observed in polycrystals, a distribution of interface thicknesses is obtained. Since the shape and the parameters of the nonlocal CZM depend on the interface thickness, a distribution of interface fracture energies is obtained as a consequence of the randomness of the material microstructure. Using these data, fracture mechanics simulations are performed and the homogenized stress-strain curves of 2D representative volume elements (RVEs) are computed. Failure is the result of a diffuse microcrack pattern leading to a main macroscopic crack after coalescence, in good agreement with the experimental observation. Finally, testing microstructures characterized by different average grain sizes, the computed peak stresses are found to be dependent on the grain size, in agreement with the trend expected according to the Hall-Petch law.
Authors and Affiliations
Marco Paggi, P. Wriggers
Keywords
Related Articles
- EP ID EP160768
- DOI 10.3221/IGF-ESIS.17.01
- Views 77
- Downloads 0
Crack tip fields and mixed mode fracture behaviour of progressively drawn pearlitic steel
This paper deals with the influence of the cold drawing process on the fracture behaviour of pearlitic steels. To this end, fracture tests under axial loading were performed on steel wires with different drawing...
Incorporation of Mean/Maximum Stress Effects in the Multiaxial Racetrack Filter
This work extends the Multiaxial Racetrack Filter (MRF) to incorporate mean or maximum stress effects, adopting a filter amplitude that depends on the current stress level along the stress or strain path. In this...
A new micromechanical model of CNT-metal nanocomposites with random clustered distribution of CNTs
Uniform dispersion of carbon nanotubes (CNTs) is a key issue for utilization of their reinforcement potential in CNT-reinforced metal matrix nanocomposites (MMNCs). It was reported that CNT clusters often exist i...
Simulation of accelerated strip cooling on the hot rolling mill run-out roller table
A mathematical model of the thermal state of the metal in the run-out roller table continuous wide hot strip mill. The mathematical model takes into account heat generation due to the polymorphic γ → α transforma...
Effect of centrifugal load on crack path in thin-rimmed and webbed gears
Thin rimmed and webbed gears are used in particular applications to reduce systems weight. This kind of gears need an accurate and fail safe design. As a matter of fact, a possible failure, due to bending fatigue,...