Loading...
Search for:
distribution-of-dislocations
0.006 seconds
Compaction simulation of nano-crystalline metals with molecular dynamics analysis
, Article MATEC Web of Conferences, 4 July 2016 through 7 July 2016 ; Volume 80 , 2016 ; 2261236X (ISSN) ; Rezaei Sameti, A ; Mofatteh, H ; Babaei, M ; Sharif University of Technology
EDP Sciences
2016
Abstract
The molecular-dynamics analysis is presented for 3D compaction simulation of nano-crystalline metals under uniaxial compaction process. The nano-crystalline metals consist of nickel and aluminum nano-particles, which are mixed with specified proportions. The EAM pair-potential is employed to model the formation of nano-particles at different temperatures, number of nano-particles, and mixing ratio of Ni and Al nano-particles to form the component into the shape of a die. The die-walls are modeled using the Lennard-Jones inter-atomic potential between the atoms of nano-particles and die-walls. The forming process is model in uniaxial compression, which is simulated until the full-dense...
Investigation of the effect of pad geometry on flat and rounded fretting fatigue
, Article Scientia Iranica ; Volume 15, Issue 3 , 2008 , Pages 332-339 ; 10263098 (ISSN) ; Farrahi, G. H ; Sharif University of Technology
Sharif University of Technology
2008
Abstract
In this paper, the effect of geometrical parameters on the fretting fatigue of a half-plane in contact with a flat and rounded pad is studied. This is accomplished by calculating and comparing the stress states and stress intensity factors of fretting cracks for a number of pad geometries. The pad geometry is represented by the radius of its rounded corners and the width of its central flat part. The distribution of dislocation method is employed to calculate the stress intensity factors of fretting induced cracks of different lengths for different values of geometrical parameters. The results of this study can be insightful for improving the geometrical design of an aero-engine compressor...
Numerical investigation of crack orientation in the fretting fatigue of a flat rounded contact
, Article International Journal of Engineering, Transactions B: Applications ; Volume 23, Issue 3-4 , 2010 , Pages 223-232 ; 1728-144X (ISSN) ; Farrahi, G. H ; Sharif University of Technology
Materials and Energy Research Center
2010
Abstract
The growth of slant cracks by fretting fatigue of a half plane in contact with a flat rounded pad was studied. The mode I and mode II stress intensity factors for cracks of various lengths and directions were calculated using the semi-analytical method of the distribution of dislocations, and their cumulative effect on the crack growth was investigated using the strain energy density criterion. The results showed dominance of mode I fracture on crack growth, and based on the observation of strain energy density factor versus crack orientation, the results also suggest that depending on the crack length, the most critical orientations of cracks are at 0° to 20° outward the contact zone. Good...