Journal ArticleDOI
Necking of anisotropic micro-films with strain-gradient effects
TLDR
In this article, the authors investigated the effect of anisotropic hardening on the nominal stress of aluminum microfilms by considering tension of a specimen with an initial imperfection used to onset localisation.Abstract:
Necking of stubby micro-films of aluminum is investigated numerically by considering tension of a specimen with an initial imperfection used to onset localisation. Plastic anisotropy is represented by two different yield criteria and strain-gradient effects are accounted for using the visco-plastic finite strain model. Furthermore, the model is extended to isotropic anisotropic hardening (evolving anisotropy). For isotropic hardening plastic anisotropy affects the predicted overall nominal stress level, while the peak stress remains at an overall logarithmic strain corresponding to the hardening exponent. This holds true for both local and nonlocal materials. Anisotropic hardening delays the point of maximum overall nominal stress.read more
Citations
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Effects of Plastic Anisotropy and Void Shape on Full Three-Dimensional Void Growth
TL;DR: In this paper, the effect of plastic anisotropy on void growth was investigated for three dimensional unit cells initially containing a void, including oblate, prolate or general ellipsoidal voids.
Journal ArticleDOI
A new macroscopically anisotropic pressure dependent yield function for metal matrix composite based on strain gradient plasticity for the microstructure
TL;DR: In this paper, a metal matrix composites with long aligned elastic fibers are studied using an energetic rate independent strain gradient plasticity theory with an isotropic pressure independent yield function at the microscale.
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Effects of anisotropy and void shape on cavitation instabilities
TL;DR: In this article, the influence of plastic anisotropy on cavitation instabilities is studied by analyzing full 3D cell models containing a small void, represented by an elastic-viscoplastic material with a small rate hardening exponent, and different 3D stress states are considered in the range of high stress triaxialities where the occurrence of cavitation infabilities can be expected.
Multi-scale modeling of composites
TL;DR: In this article, a phenomenologically macroscopic model for metal matrix composites is developed based on constitutive operators describing the elastic behavior and the trapped free energy in the material, in addition to the plastic behavior in terms of the anisotropic development of the yield surface.
References
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Book
The mathematical theory of plasticity
TL;DR: In this paper, the solution of two-dimensional non-steady motion problems in two dimensions is studied. But the solution is not a solution to the problem in three dimensions.
Journal ArticleDOI
Indentation size effects in crystalline materials: A law for strain gradient plasticity
William D. Nix,Huajian Gao +1 more
TL;DR: In this article, the indentation size effect for crystalline materials can be accurately modeled using the concept of geometrically necessary dislocations, which leads to the following characteristic form for the depth dependence of the hardness: H H 0 1+ h ∗ h where H is the hardness for a given depth of indentation, h, H 0 is a characteristic length that depends on the shape of the indenter, the shear modulus and H 0.
Journal ArticleDOI
A theory of the yielding and plastic flow of anisotropic metals
TL;DR: In this article, a theory is suggested which describes the yielding and plastic flow of an anisotropic metal on a macroscopic scale and associated relations are then found between the stress and strain-increment tensors.
Journal ArticleDOI
Strain gradient plasticity: Theory and experiment
TL;DR: In this paper, a deformation theory of plasticity is introduced to represent in a phenomenological manner the relative roles of strain hardening and strain gradient hardening, which is a non-linear generalization of Cosserat couple stress theory.
Journal ArticleDOI
Elastic-Plastic Deformation at Finite Strains
TL;DR: In this paper, the authors generalize a previous theory to permit arbitrary deformation histories by considering two coupled thermodynamic systems: one comprising thermo- elasticity at finite strain and the other the irreversible process of dissipation and absorption of plastic work.