Interfacial cracks under low-frequency harmonic loadings

Generally, all existing structural materials contain various inter- and intra-component defects. For instance, cracks and delaminations often occur at the bonding surfaces between two dissimilar materials. The presence of these defects considerably decreases the strength and the lifetime of the structures as well as significantly increases the cost of exploitation. Therefore it is necessary to understand the mechanism of fracture in cracked materials and to ensure that the residual strength of the structure will not fall below an acceptable level over the required service life. The majority of previous studies are limited by the case of cracked homogeneous solids due to the substantial complications in solution of such problems in heterogeneous materials. However the industry requires solutions of much more complex problems involving composite structures with cracks subjected to dynamic loading.

Layered material with cracks An interface crack between two half-spaces

The current project is devoted to a 2-D problem for interface cracks located between two dissimilar materials under harmonic external loading. The system of boundary integral equations for displacements and tractions is derived from the dynamic Somigliana identity. The distributions of the displacements and tractions at the bonding interface and the surface of the cracks are analysed for the normally incident harmonic waves. The dynamic stress intensity factors are also computed for different values of the frequency of the incident wave and different material properties.



Tangential displacements at the bonding interface




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