Stress intensity factors of edge crack specimens under hydrostatic compression with application to measuring fracture toughness of rock

1976 ◽  
Vol 12 (2) ◽  
pp. 320-322 ◽  
Author(s):  
R. A. Schmidt ◽  
S. E. Benzley
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Edge Crack ◽  
Hydrostatic Compression ◽  
Intensity Factors

Experimental Determination of KI for Short Internal Cracks

2001 ◽  
Vol 68 (6) ◽  
pp. 937-943 ◽  
Author(s):  
K. Bearden ◽  
J. W. Dally ◽  
R. J. Sanford
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Edge Crack ◽  
Series Solution ◽  
Experimental Studies ◽  
Experimental Methods ◽  
Internal Crack ◽  
Intensity Factors ◽  
Mode Stress

Since the pioneering discussion by Irwin, a significant effort has been devoted to determining stress intensity factors (K) using experimental methods. Techniques have been developed to determine stress intensity factors from photoelastic, strain gage, caustics, and moire´ data. All of these methods apply to a relatively long single-ended-edge crack. To date, the determination of K for internal cracks that are double-ended by experimental methods has not been addressed. This paper describes a photoelastic study of tension panels with both central and eccentric internal cracks. The data recorded in the experiments was analyzed using a new series solution for the opening-mode stress intensity factor for an internal crack. The data was also analyzed using the edge-crack series solution, which is currently employed in experimental studies. Results indicated that the experimental methods usually provided results accurate to within three to five percent if the series solution for the internal crack was employed in an overdeterministic numerical analysis of the data. Comparison of experimental results using the new series for the internal crack and the series for an edge crack showed the superiority of the new series.

Effects of the Length of Carbon Nanotube (CNT) in CNT Reinforced Composites

2006 ◽  
Vol 324-325 ◽  
pp. 855-858
Author(s):  
Q. Wang ◽  
X. F. Sun ◽  
Kimihiro Ozaki
Keyword(s):  
Fracture Toughness ◽  
Carbon Nanotube ◽  
Stress Intensity ◽  
Stress Field ◽  
Stress Intensity Factors ◽  
Reinforced Composites ◽  
Intensity Factors ◽  
Singular Stress ◽  
Singular Stress Field

In this paper, the strength of the singular stress field near the ends of the CNTs in composites was analyzed to clarify the effects of the CNT length on stress filed in the CNT reinforced composites when studying the fracture toughness. The singular stress field was separated into two types of singularities, symmetric and skew-symmetric, near the ends of CNTs according to the deformation and loading types. The stress intensity factors of the singular stress field were calculated for these two types of singularities. The effects of the CNT length in CNT reinforced composites on these stress intensity factors were investigated.

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