Size effects on stability and bifurcation of nonlinear viscoelastic microcantilevers based on strain gradient

2021 ◽  
Vol 44 (1) ◽  
Author(s):  
Farshad Taheran ◽  
Mohammad Taghi Ahmadian ◽  
Vahid Monfared ◽  
Davood Toghraie
Keyword(s):  
Strain Gradient ◽  
Size Effects ◽  
Stability And Bifurcation ◽  
Nonlinear Viscoelastic

Scale-Dependent Crack Modeling for Investigation the Effect of Geometrically Necessary Dislocations in Micro/Nano Grain Size of Copper

2016 ◽  
Vol 15 ◽  
pp. 1-16 ◽  
Author(s):  
Amin Zaami ◽  
Ali Shokuhfar
Keyword(s):  
Grain Size ◽  
Stress Concentration ◽  
Strain Gradient ◽  
Stress Concentration Factor ◽  
Size Effects ◽  
Crack Tip ◽  
Length Scale ◽  
State Variables ◽  
Dependent Model ◽  
Homogeneous Strain

In this study, a scale-dependent model is employed to investigate the size effects of copper on the behavior of the crack-tip. This model includes the homogeneous and non-homogeneous strain hardening based on the wavelet interpretation of size effect. Introducing additional micro/nano structural considerations together with decreasing grain size, different size effects can be obtained. As the size dependency is not taken into account in conventional plasticity, an enhanced theory which is related to the strain gradient introduces a length scale will give more realistic representations of state variables near the crack-tip. Accordingly, the contribution of geometrically necessary dislocations (GNDs) activity on strengthening and stress concentration factor is identified in the crack-tip. Finally, the affected zone which is dominated by presence of GNDs is identified

Strain gradient and wavelet interpretation of size effects in yield and strength

2003 ◽  
Vol 35 (8) ◽  
pp. 733-745 ◽  
Author(s):  
I. Tsagrakis ◽  
A. Konstantinidis ◽  
E.C. Aifantis
Keyword(s):  
Strain Gradient ◽  
Size Effects
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