scholarly journals A coupled FFM model to interpret fracture toughness values for brittle materials

2016 ◽  
Vol 2 ◽  
pp. 1983-1990
Author(s):  
Donato Firrao ◽  
Paolo Matteis ◽  
Alberto Sapora ◽  
Pietro Cornetti ◽  
Alberto Carpinteri
Keyword(s):  
Fracture Toughness ◽  
Brittle Materials

scholarly journals On the Use of Approximation Methods for Microcrack Shielding Problems

1992 ◽  
Vol 59 (3) ◽  
pp. 497-501 ◽  
Author(s):  
H. Cai ◽  
K. T. Faber
Keyword(s):  
Fracture Toughness ◽  
Numerical Solution ◽  
Experimental Evidence ◽  
Discrete Model ◽  
Brittle Materials ◽  
Approximation Methods ◽  
Exact Formulation

There is experimental evidence that stress-induced microcracking near a macrocrack tip enhances the fracture toughness of brittle materials. In considering the interaction of the macrocrack with multiple microcracks using a discrete model, it is essential to use approximation methods in order to keep the amount of the computation to a tractable level. However, when crack distances are small, the results of the approximation methods can be significantly different from the numerical solution based upon the exact formulation. The results obtained by these approximation methods will be compared with the numerical solution to show the applicability ranges in which the errors are acceptably small. The use of results obtained by the approximation methods outside applicability ranges in literature is shown to lead to incorrect conclusions concerning microcrack shielding.

Fracture toughness and absorbed energy measurements in impact tests on brittle materials

1973 ◽  
Vol 8 (7) ◽  
pp. 949-956 ◽  
Author(s):  
G. P. Marshall ◽  
J. G. Williams ◽  
C. E. Turner
Keyword(s):  
Fracture Toughness ◽  
Brittle Materials ◽  
Absorbed Energy ◽  
Impact Tests

scholarly journals Cracking During Nanoindentation and its Use in the Measurement of Fracture Toughness

1994 ◽  
Vol 356 ◽  
Author(s):  
D. S. Harding ◽  
W. C. Oliver ◽  
G. M. Pharr
Keyword(s):  
Thin Film ◽  
Fracture Toughness ◽  
Small Volume ◽  
Brittle Materials ◽  
Empirical Method ◽  
Berkovich Indenter ◽  
Empirical Constant ◽  
Cube Corner ◽  
Semi Empirical ◽  
Radial Cracks

AbstractResults of an investigation aimed at developing a technique by which the fracture toughness of a thin film or small volume can be determined in nanoindentation experiments are reported. The method is based on the radial cracking which occurs when brittle materials are deformed by a sharp indenter such as a Vickers or Berkovich diamond. In microindentation experiments, the lengths of radial cracks have been found to correlate reasonably well with fracture toughness, and a simple semi-empirical method has been developed to compute the toughness from the crack lengths. However, a problem is encountered in extending this method into the nanoindentation regime with the standard Berkovich indenter in that there are well defined loads, called cracking thresholds, below which indentation cracking does not occur in most brittle materials. We have recently found that the problems imposed by the cracking threshold can be largely overcome by using an indenter with the geometry of the corner of a cube. For the cube-corner indenter, cracking thresholds in most brittle materials are as small as 1 mN (∼ 0.1 grams). In addition, the simple, well-developed relationship between toughness and crack length used for the Vickers indenter in the microindentation regime can be used for the cube-corner indenter in the nanoindentation regime provided a different empirical constant is used.

Determination of fracture toughness and fracture energy of brittle materials under impact wedging

1996 ◽  
Vol 37 (4) ◽  
pp. 586-594 ◽  
Author(s):  
A. S. Eremenko ◽  
S. A. Novikov ◽  
V. A. Sinitsyn ◽  
V. A. Pushkov ◽  
M. M. Yakupov
Keyword(s):  
Fracture Toughness ◽  
Fracture Energy ◽  
Brittle Materials
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