Interaction between different internal length scales for strain localisation analysis of single phase materials

2003 ◽  
Vol 30 (3) ◽  
pp. 212-219 ◽  
Author(s):  
H. W. Zhang ◽  
B. A. Schrefler ◽  
P. Wriggers
Keyword(s):  
Single Phase ◽  
Strain Localisation ◽  
Internal Length ◽  
Length Scales

A micromechanics-based constitutive model for nanocrystalline shape memory alloys incorporating grain size effects

2021 ◽  
pp. 1045389X2110282
Author(s):  
Xiang Zhu ◽  
Guansuo Dui ◽  
Yicong Zheng
Keyword(s):  
Grain Size ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Size Effects ◽  
Boundary Phase ◽  
Length Scale ◽  
Internal Length ◽  
Length Scales ◽  
Size Dependent ◽  
Grain Size Effects

A micromechanics-based model is developed to capture the grain-size dependent superelasticity of nanocrystalline shape memory alloys (SMAs). Grain-size effects are incorporated in the proposed model through definition of dissipative length scale and energetic length scale parameters. In this paper, nanocrystalline SMAs are considered as two-phase composites consisting of the grain-core phase and the grain-boundary phase. Based on the Gibbs free energy including the spatial gradient of the martensite volume fraction, a new transformation function determining the evolution law for transformation strain is derived. Using micromechanical averaging techniques, the grain-size-dependent superelastic behavior of nanocrystalline SMAs can be described. The internal length scales are calibrated using experimental results from published literature. In addition, model validation is performed by comparing the model predictions with the corresponding experimental data on nanostructured NiTi polycrystalline SMA. Finally, effects of the internal length scales on the critical stresses for forward and reverse transformations, the hysteresis loop area (transformation dissipation energy), and the strain hardening are investigated.

Analytical prediction of intrinsic length scales in strain localisation

1998 ◽  
Vol 08 (PR8) ◽  
pp. Pr8-19-Pr8-27 ◽  
Author(s):  
G. Barbier ◽  
G. Rousselier ◽  
R. Lebrun ◽  
Y. Sun
Keyword(s):  
Analytical Prediction ◽  
Strain Localisation ◽  
Length Scales ◽  
Intrinsic Length

The influence of internal length scales on mechanical properties in natural nanocomposites: A comparative study on inner layers of seashells

2008 ◽  
Vol 4 (6) ◽  
pp. 1694-1706 ◽  
Author(s):  
Franziska D. Fleischli ◽  
Marianne Dietiker ◽  
Cesare Borgia ◽  
Ralph Spolenak
Keyword(s):  
Mechanical Properties ◽  
Comparative Study ◽  
Internal Length ◽  
Length Scales

The Two Dimensions Analysis of Localzation Bandwidth in Material Distortion

2012 ◽  
Vol 476-478 ◽  
pp. 2556-2560
Author(s):  
Ting Jian Dong ◽  
Gang Cheng
Keyword(s):  
Mixture Models ◽  
Lower Limit ◽  
Strain Localization ◽  
Two Dimensions ◽  
Band Width ◽  
Internal Length ◽  
Length Scales ◽  
Harmonic Motion ◽  
Simple Harmonic Motion ◽  
Rate Dependent

The paper studies strain localization and stability of material by simple harmonic motion by using rate dependent and gradient-dependent models. The laws of Internal Length Scales and stability of material are obtained at two-dimensionals condition for two mixture models. The conditions of wavelengh’s lower limit and stability of material are confirmed. Thus, a formula of strain localization band width about material at the condition of one and two dimensions is obtained.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Sign in / Sign up

Export Citation Format

Share Document