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interfacial-damage
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Phase field approach for nanoscale interactions between crack propagation and phase transformation
, Article Nanoscale ; Volume 11, Issue 46 , 2019 , Pages 22243-22247 ; 20403364 (ISSN) ; Levitas, V. I ; Farrahi, G. H ; Javanbakht, M ; Sharif University of Technology
Royal Society of Chemistry
2019
Abstract
The phase field approach (PFA) for the interaction of fracture and martensitic phase transformation (PT) is developed, which includes the change in surface energy during PT and the effect of unexplored scale parameters proportional to the ratio of the widths of the crack surface and the phase interface, both at the nanometer scale. The variation of these two parameters causes unexpected qualitative and quantitative effects: shift of PT away from the crack tip, "wetting" of the crack surface by martensite, change in the structure and geometry of the transformed region, crack trajectory, and process of interfacial damage evolution, as well as transformation toughening. The results suggest...
Effective anti-plane moduli of couple stress composites containing elliptic multi-coated nano-fibers with interfacial damage and variational bounds
, Article International Journal of Damage Mechanics ; Volume 30, Issue 9 , 2021 , Pages 1351-1376 ; 10567895 (ISSN) ; Shodja, H. M ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Prediction of the anti-plane moduli of solids consisting of a given distribution of unidirectionally aligned elliptic multi-coated fibers with interfacial damage is the focus of this paper. The fibers and their coating layers may be in the order of nano or micro scales. All the constituent phases of the composite are supposed to be described in terms of couple stress elasticity. Accordingly, the bounds for the overall shear moduli of the aforementioned composites are provided by employing the principles of minimum potential and complementary energies. Certain subtleties associated with the elliptic multi-coated fibers for three cases of pure sliding (completely damaged), imperfect (partially...
Variational bounds and overall shear modulus of nano-composites with interfacial damage in anti-plane couple stress elasticity
, Article International Journal of Damage Mechanics ; Volume 29, Issue 2 , 2020 , Pages 246-271 ; Hashemian, B ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
It is well known that classical continuum theory has certain deficiencies in capturing the size effects and predicting the nanoscopic behavior of materials in the vicinity of nano-inhomogeneities and nano-defects with reasonable accuracy. Couple stress theory which is associated with an internal length scale for the medium is one of the higher order continuum theories capable of overcoming such difficulties. In this work, the problem of a nano-size fiber embedded in an unbounded isotropic elastic body for three different types of interface conditions: perfect, imperfect (partially damaged), and pure sliding (completely damaged) subjected to remote anti-plane loading is examined in this...
Behavior of Composites Containing Multi-coated Nano-fibers with Interfacial Damage in Couple Stress Theory
, Ph.D. Dissertation Sharif University of Technology ; Mohammadi Shodja, Hossein (Supervisor)
Abstract
It is well-known that classical continuum theory has certain deficiencies in capturing the size effects and predicting the nanoscopic behavior of materials in the vicinity of nano-inhomogeneities and nano-defects with reasonable accuracy. Couple stress theory which is associated with an internal length scale for the medium is one of the higher order continuum theories capable of overcoming such difficulties. Since most reinforcements may not be perfectly bonded to their surrounding matrix, the perfect bonding condition is often inadequate in describing the physical and mechanical behavior of real composite materials. In this work, the problem of a nano-size fiber embedded in an unbounded...