Fracture mechanics analysis

Crack Tip Stresses. The simplest case for fracture mechanics analysis is a linear elastic material where stress. O, is proportional to strain, S,... 

A partial answer to the first question has been provided by a theoretical treatment (1,2) that examines the conditions under which a matrix crack will deflect along the iaterface betweea the matrix and the reinforcement. This fracture—mechanics analysis links the condition for crack deflection to both the relative fracture resistance of the iaterface and the bridge and to the relative elastic mismatch between the reinforcement and the matrix. The calculations iadicate that, for any elastic mismatch, iaterface failure will occur whea the fracture resistance of the bridge is at least four times greater than that of the iaterface. For specific degrees of elastic mismatch, this coaditioa can be a conservative lower estimate. This condition provides a guide for iaterfacial desiga of ceramic matrix composites. 

Fracture mechanics analysis requires the determination of the mode I stress intensity factor for a surface crack having a circular section profile. Here the circular section flaw will be approximated by a semi-elliptical flaw. 

E. P. Kennedy, Fracture Mechanics Analysis of Extruded Graphite, Extended Abstracts and Program-lb Biennial Conference on Carbon, Pub American Carbon Society, 1985, pp 287 288. 

For brittle failures we may use the fracture mechanics analysis introduced in the previous sections. From equations (2.96) and (2.99) we may write... 

Sometimes the failure occurs by propagation of a crack that starts at the top and travels downward until the interface is completely debonded. In this case, the fracture mechanics analysis using the energy balance approach has been applied [92] in which P, relates to specimen dimensions, elastic constants of fiber and matrix, initial crack length, and interfacial work of fracture (W,). 

Doll, W. Optical Interference Measurements and Fracture Mechanics Analysis of Crack Tip Craze Zones. Vol. 52/53, pp. 105 — 168. 

Niihara K., 1983, A fracture mechanics analysis of indentation-induced Palmquist crack in ceramics, J. Mater. Sci., Lett. 2, 221. 

Fracture Mechanics Analysis of Crack Tip Craze Zones... 

Optical Interference Measurements and Fracture Mechanics Analysis... 

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