Interfacial stress intensity factor

ISIF interfacial stress intensity factor KB kilobyte (1,000 bytes)... 

Furthermore, the energy-release rate G for crack advance along the interface is related to the complex interfacial stress-intensity factor by... 

These last two aspects have led several workers [10,34,35] to suggest that for cracks at, or near, an interface a combined interfacial stress intensity factor, Kic, for crack growth may be defined such that ... 

As discussed above, many of the most severe problems associated with a stress intensity factor approach to cracking along, or close to, interfaces may be circumvented if a combined interfacial stress intensity factor, is defined and therefore only a single geometry factor, Qi, has to be determined. This approach has been adopted by several workers [10,34,35,52] and values of Qi... 

The assumption was then made that the amount of water in the outer debonded zone of the joint exceeded the critical water concentration, while in the central zone, still unaffected by environmental exposure, it was below the critical level. The extent of interfacial debonding that occurred on environmental exposure can be considered equivalent to the environmental crack length, a, needed to relate the stress intensity factor, Xj, to the fracture stress, ay, of the joint (Eq. 5). 

Let us now proceed to the actual determination of the stress intensity factors and phase angles necessary for interfacial fracture analysis of coatings. As mentioned earlier, Hutchinson, Suo and their coworkers solved the problem of an interfacial... 

Fig. 29. Parametric study of the local mode II stress intensity factor /fn versus the non-dimensional location of the sub-interfacial craek for different material combinations. The applied strain energy release rale used in the calculation was 310 J/m. ...

However, even this approach needs an additional characteristic length. Reddy and Guess proposed the use of the critical intensity factors of the interface comer stress for the prediction of the interfacial quality. The so-called dominance zone of the stress intensity factor must be larger than the plastic zone in this case. This is a reasonable assumption only for certain materials, e.g., ceramics and cleavage fracture of metals, but not for polymers. 

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