Investigator: prof. RNDr. Zdeněk Knésl, CSc.
Number of Project: 101/05/0320
Agency: Czech Science Foundation
Duration: 01. 01. 2005 - 31. 12. 2007

An increasing exploitation of composite materials, protective surface layers, thermal barriers or functionally gradient materials requires to extend safety assessment approaches of the fracture mechanics, originally developed for isotropic homogeneous materials, to the field of
anisotropic, strongly heterogeneous media. A typical situation is that of crack at the interface of anisotropic materials, like neighbouring plies in laminates, matrix/fibre or surface layer/substrate interfaces. The problem is further complicated due to crack face bridging by
particles or fibres and non-linear material response in the wake of crack respectively. Recently, the technique of so-called two state interaction integrals has been increasingly applied to the evaluation of fracture mechanics parameters. A necessary condition for success
of this approach is the existence of an ”auxiliary” solution. The project will aim to develop an effective tool for the determination of (generalised) stress intensity factors as well as T-stresses for anisotropic body with bimaterial interface via the combination of FEM and
continuously distributed dislocation (CDD) technique. The CDD technique will be used for finding an ”auxiliary” solution entering the two-state interaction integrals and, conversely, FEM will be applied in construction of fundamental solution for dislocation in finite
anisotropic bimaterial body.

Kotoul, M., Vysloužil, T., Boccaccini, A. R., Dlouhý, I.: Crack growth in glass matrix composite reinforced by long SiC fibres; Theoretical and applied fracture mechanics 49, No. 2, 2008, pp. 158-170 doi:10.1016/j.tafmec.2007.11.001.

Šestáková, L., Náhlík, L., Hutař, P., Knésl, Z., Fracture mechanics parameters of multilayer pipes, Applied and Computational Mechanics, Vol. 1, 299-306, 2007

Klusák, J., Knésl, Z.: Determination of crack initiation direction from a bi-material notch based on the strain energy density concept, Computational Materials Science (2007), Volume 39, issue 1, pp. 214-218.

Klusák, J., Knésl, Z., Náhlík, L. Crack initiation criteria for singular stress concentrations, Part II: Stability of sharp and bi-material notches, Vol. 14, No. 6, pp. 409-422, 2007

Knésl, Z., Klusák, J., Náhlík, L. Crack initiation criteria for singular stress concentrations, Part I: A universal assessment of singular stress concentrations, Vol. 14, No. 6, pp. 399-408, 2007

Náhlík, L., Hutař, P., Knésl, Z., The influence of loading ratio on fatigue crack propagation through a bi-material interface, Key Engineering Materials, Vols. 348-349, 317-320, 2007

Náhlík, L., Hutař, P., Knésl, Z., Transverse cracking of layered structures: evaluation of fatigue crack propagation, Materials Science Forum, Vols. 565-568, pp. 221-224, 2007

Náhlík, L., Šestáková, L., Hutař, P., Estimation of the crack propagation direction of a crack touching the interface between two elastic materials, Materials Science Forum, Vols. 565-568, pp. 225-228, 2007

Hutař, P., Seitl, S., Knésl, Z., The role of the constraint in the case of short cracks, Material Science Forum, Vol. 482, 2005, pp. 303-306