scholarly journals The mechanism of the recrystallization process in epitaxial GaN under dynamic stress field: atomistic origin of planar defect formation

2009 ◽  
Vol 40 (12) ◽  
pp. 1881-1884 ◽  
Author(s):  
C. R. Das ◽  
S. Dhara ◽  
H. C. Hsu ◽  
L. C. Chen ◽  
Y. R. Jeng ◽  
...  
Keyword(s):  
Stress Field ◽  
Dynamic Stress ◽  
Defect Formation ◽  
Planar Defect ◽  
Recrystallization Process ◽  
Dynamic Stress Field

Dynamic Steady-State Stress Field in a Web During Slitting

2005 ◽  
Vol 72 (2) ◽  
pp. 157-164 ◽  
Author(s):  
C. Liu ◽  
H. Lu ◽  
Y. Huang
Keyword(s):  
Steady State ◽  
Fracture Mechanics ◽  
Stress Field ◽  
Dynamic Fracture ◽  
Dynamic Stress ◽  
Razor Blade ◽  
Dynamic Fracture Mechanics ◽  
Mechanics Analysis ◽  
Dynamic Stress Field ◽  
The Web

Based on a dynamic fracture mechanics analysis, the stress field in a continuous film (called a web) during slitting (or cutting) is investigated. For a homogeneous, isotropic and linearly elastic web, the steady-state dynamic stress field surrounding the slitter blade can be related to the interacting traction between the moving web and the blade, and to the far-field tension that is parallel to the slitting direction. The interaction between the moving web and the blade also includes friction that is considered to be a Coulomb type. By solving an integral equation, the normal traction between the web and the blade can be expressed as a function of the blade profile and the web speed. Numerical calculations are performed for an ideal razor blade with the wedge shape. The analysis presented in this study indicates that the contact between the moving web and the blade does not start at the tip of the blade but rather starts at some distance behind the blade tip. Moreover, it is found that the distance from the point where the web begins to separate to the point where the blade and the web start to have contact, is controlled by the toughness of the web material and also by the web speed. Some characteristic nature of the dynamic stress field surrounding the slitter blade is investigated based on the dynamic fracture mechanics analysis results.

The Dynamic Stress Field in the Matrix Surrounding a Spheroidal Particle

2002 ◽  
Vol 36 (15) ◽  
pp. 1803-1824 ◽  
Author(s):  
R. Paskaramoorthy ◽  
F. Kienhöfer ◽  
S. A. Meguid
Keyword(s):  
Stress Field ◽  
Dynamic Stress ◽  
Spheroidal Particle ◽  
Dynamic Stress Field ◽  
The Matrix

On the Characterization of the Transient Stress Field Near the Tip of a Crack

1987 ◽  
Vol 54 (1) ◽  
pp. 72-78 ◽  
Author(s):  
K. Ravi-Chandar ◽  
W. G. Knauss
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Field ◽  
Dynamic Stress ◽  
Dynamic Stress Intensity Factor ◽  
Crack Tip ◽  
Transient Conditions ◽  
Dynamic Stress Field

The dynamic stress field near a propagating crack tip is usually characterized in terms of one parameter, namely, the dynamic stress intensity factor. While analytically this is an exact representation at the crack tip itself, under transient conditions, the domain of dominance of the stress intensity factor varies as discussed by Ma and Freund (1986). In this paper, we present experimental results which show that while the stress intensity factor may dominate the near tip stress field under transient conditions as long as the crack velocity is small, it may not be dominant over an appreciable region under other transient conditions of crack tip motion, thus making it difficult to determine this quantity experimentally.

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