scholarly journals Quantitative Characterization of Mechanical Stress Field and Fracture Strength in Isotropic Brittle Materials During Crack Tip Propagation

2014 ◽  
Vol 97 (12) ◽  
pp. 3853-3856 ◽  
Author(s):  
Roberto Dugnani ◽  
Ricardo J. Zednik
2003 ◽  
Vol 233-236 ◽  
pp. 127-132
Author(s):  
Isamu Oda ◽  
Andrew Willett ◽  
Mitsuharu Yamamoto ◽  
Mitsuru Miyawaki ◽  
Naoki Watanabe ◽  
...  

1999 ◽  
Vol 5 (S2) ◽  
pp. 162-163
Author(s):  
Y. Yao ◽  
A.R. Thölén

A comprehensive understanding of the relation between structure and properties in nano-materials calls for an extensive knowledge of the adhesion between nanoparticles. Electron diffraction contrast from the stress field caused by adhesion between contacting particles yields a detailed information on surface energy, grain boundary energy, dislocation and interphase formation mechanisms. However, the image interpretation is hindered by the scarcity of defined image condition data to fit the theoretical simulations due to the non-trivial TEM experimental situation on such a nanometric scale.In our contribution, we challenge the above characterization complications by initiating CBED, HREM, and EELS on contacting nanoparticles with a CM200 FEG TEM. The main objective of our investigation is a quantitative simulation of the contacting stress field images from contacting nanoparticles and a quantitative characterization of the adhesion properties. In our approach, we started with cobalt particles which were coherently precipitated in a Cu-Co0.2wt% alloy, and then extracted using the carbon evaporation replica technique.


1987 ◽  
Vol 54 (1) ◽  
pp. 72-78 ◽  
Author(s):  
K. Ravi-Chandar ◽  
W. G. Knauss

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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