Opening of a System of Cracks - on the Mechanism of Cyclic Lateral Eruption of the St. Helens Volcano in 1980

Keyword(s):  
1990 ◽  
Vol 57 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Asher A. Rubinstein

The material-toughening mechanism based on the crack-path deflection is studied. This investigation is based on a model which consists of a macrocrack (semi-infinite crack), with a curvilinear segment at the crack tip, situated in a brittle solid. The effect of material toughening is evaluated by comparison of the remote stress field parameters, such as the stress intensity factors (controlled by a loading on a macroscale), to effective values of these parameters acting in the vicinity of a crack tip (microscale). The effects of the curvilinear crack path are separated into three groups: crack-tip direction, crack-tip geometry pattern-shielding, and crack-path length change. These effects are analyzed by investigation of selected curvilinear crack patterns such as a macrocrack with simple crack-tip kink in the form of a circular arc and a macrocrack with a segment at the crack tip in the form of a sinusoidal wave. In conjunction with this investigation, a numerical procedure has been developed for the analysis of curvilinear cracks (or a system of cracks) in a two-dimensional linear elastic solid. The formulation is based on the solution of a system of singular integral equations. This numerical scheme was applied to the cases of finite and semi-infinite cracks.


Soft Matter ◽  
2015 ◽  
Vol 11 (40) ◽  
pp. 7995-8012 ◽  
Author(s):  
Ramin Ghelichi ◽  
Ken Kamrin

The problem of predicting the growth of a system of cracks, each crack influencing the growth of the others, arises in multiple fields.


2009 ◽  
Vol 55 (1) ◽  
pp. 8-16 ◽  
Author(s):  
E. V. Glushkov ◽  
N. V. Glushkova ◽  
M. V. Golub ◽  
Ch. Zhang

1989 ◽  
Vol 174 ◽  
Author(s):  
V. J. Laraia ◽  
A. H. Heuer

AbstractAn investigation of the relationship between structure and mechanical behavior is reported for mollusk shells employing foliated, nacreous, and crossed-lamellar structures by microindentation in the Knoop and Vickers geometries. Indentation damage zones develop crack systems that reflect the micro-architecture. For the crossed-lamellar structure, the system of cracks about the indentation normally developed in a brittle material is suppressed. Previous reports that shells are harder than the corresponding minerals, calcite and aragonite, are confirmed, but it is found that this effect can be strongly dependent on orientation. This anomalous hardness is not an artifact of the identation test technique, since scratch tests confirm the relative hardness of shell over the mineral. It is suggested that microstructural organization is of central importance in producing this hardness, as opposed to intrinsic properties of the mineral or matrix phases.


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