On spherical nanoindentation stress-strain curves, creep and kinking nonlinear elasticity in brittle hexagonal single crystals

2021 ◽  
Author(s):  
Sandip Basu
Keyword(s):  
Single Crystals ◽  
Nonlinear Elasticity ◽  
Stress Strain

A Continuum Model for Single Crystal Cyclic Plasticity

2003 ◽  
Vol 779 ◽  
Author(s):  
Biqiang Xu ◽  
Yanyao Jiang
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Kinematic Hardening ◽  
Strain Curve ◽  
Cyclic Behavior ◽  
Cyclic Plasticity ◽  
Amplitude Dependence ◽  
Slip Systems ◽  
Stress Strain ◽  
Copper Single Crystals

AbstractA constitutive model was developed to bridge the cyclic plasticity behavior of single crystals and the corresponding characteristic dislocation structures. Yield and flow were built on the individual slip systems. The Armstrong-Frederick kinematic hardening rule was invoked to capture the Bauschinger effect. A material memory parameter was introduced to consider the amplitude dependence of cyclic hardening. Latent hardening considering the interactions among the slip systems was used to describe the anisotropic cyclic behavior. The experimental results of copper single crystals were used to validate the model developed. It was found that the model was able to adequately describe the well-known three distinctive regions in the cyclic stress-strain curve of the FCC single crystal oriented for single slip and the associated dislocation substructures. The model was capable of capturing the enhanced hardening observed in copper single crystals in multi-slip orientations. For a given loading history, the model can predict not only the saturated stress-strain response but also the detailed evolution of the transient cyclic behavior. The characteristic dislocation structures can be featured with the slip evolution.

Orientation-dependent Constitutive Model with Nonlinear Elasticity for Shocked β-HMX Single Crystal

2012 ◽  
Vol 13 (1) ◽  
Author(s):  
Yan-Qing Wu ◽  
Feng-Lei Huang
Keyword(s):  
Constitutive Model ◽  
Single Crystal ◽  
Mechanical Behavior ◽  
Single Crystals ◽  
Nonlinear Elasticity ◽  
Chemical Reactions ◽  
Crystal Plasticity ◽  
Orientation Dependence ◽  
Plasticity Model ◽  
Crystal Plasticity Model

AbstractAs orientation-dependence of shock-induced thermal responses and chemical reactions in energetic single crystals are related to anisotropic mechanical behavior, a crystal plasticity model for low-symmetric

Derivation of Polycrystal Creep Properties From the Creep Data of Single Crystals

1977 ◽  
Vol 44 (1) ◽  
pp. 73-78 ◽  
Author(s):  
T. H. Lin ◽  
C. L. Yu ◽  
G. J. Weng
Keyword(s):  
Single Crystals ◽  
Creep Deformation ◽  
Tensile Loading ◽  
Present Theory ◽  
Sole Source ◽  
Stress And Strain ◽  
Creep Data ◽  
Stress Strain ◽  
Macroscopic Stress ◽  
Additional Constant

A method developed for calculating the polycrystal stress-strain-time relation from the creep data of single crystals is shown. Slip is considered to be the sole source of creep deformation. This method satisfies, throughout the aggregate, both the condition of equilibrium and that of continuity of displacement as well as the creep characteristics of single crystals. A very large three-dimensional region is assumed to be filled with innumerable identical cubic blocks, each of which consists of 64 cube-shaped crystals of different orientations. This region is assumed to be embedded in an infinite elastic isotropic medium. This infinite medium is subject to a uniform loading. The average stress and strain of a cubic block at the center of the region is taken to represent the macroscopic stress and strain of the polycrystal. This method is self-consistent and considers the heterogeneous interaction effect of the creep deformation of all slid crystals. The macroscopic stress-strain-time relations of the polycrystal were calculated for three tensile loadings, one radial loading, and two nonradial loadings of combined tension and torsion. The numerical results given by the present theory agree well with those predicted by the so-called “Mechanical Equation of State.” The creep strain components calculated by the present theory for the case of a constant tensile loading followed by an additional constant tensile loading are found to be considerably higher than those predicted by von Mises and Tresca’s theories. These results agree well qualitatively with experimental results.

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