Investigator: doc. Ing. Luboš Náhlík, Ph.D.
Number of Project: 106/04/P084
Agency: Czech Science Foundation
Duration: 01. 01. 2004 - 31. 12. 2006

Suggested project deals with behaviour and propagation of a fatigue crack near and through bi-material interface. It makes wider and more general results from solution of project GA ČR 106/01/0381 "Propagation of a fatigue crack through the interface between two materials", where was solved this problem with assumption of ideal interface between two elastic materials. The project is aimed to consider more realistic interface model and more general behaviour of both materials (influence of anisotropy and plasticity of both materials).
Presumptive results make it possible quantitative description of crack propagation rate for crack propagated through the material interface. The result makes it possible an estimation of residual fatigue life of composite bodies. Calculated threshold values for fatigue crack propagation with crack tip at the bi-material interface can for given conditions estimate whether the cracks will stop or will propagate to the second material. These questions relate with an estimation of residual fatigue life of composite bodies with desiderative properties. The results of project solution contribute to a better understanding of the fatigue damage of composite materials and bring in a new knowledge in the field of fracture mechanics.

Knésl, Z., Náhlík, L., Bareš, P. Failure behaviour of coated structures. Journal of Computational and Applied Mechanics, Vol. 7, No. 2, 2006.

L. Náhlík, Z. Knésl, F. Kroupa: Interaction of a crack in the plasma-sprayed ceramic coating with the metal substrate. Materials Science Forum, Vol. 482, 2005, pp. 223-226.

L. Náhlík: Crack trapping in the interface between matrix and inclusion. Engineering Mechanics, Vol. 11, No. 5, ISSN 1210-2717, 2004, pp. 371-375.

F. Kroupa, L. Náhlík, Z. Knésl: Crack growth in thermally sprayed ceramic coatings. Acta Technica CSAV 49, No. 2, 2004, pp. 149-168.

Náhlík, L., Hutař, P., Knésl, Z. Influence of residual stresses on threshold values for crack propagation through an interface between two materials. Key Engineering Materials, Vol. 325, p. 1153-1156, 2006.

Náhlík, L. Estimation of the fatigue threshold values for a crack propagating through a bi-material interface taking into account residua stresses. Materials and Technology (Materiali in Tehnologije), Vol. 40, No. 4, p. 157-160, Ljublana 2006.