Investigator: Ing. Pavel Hutař, Ph.D.
Number of Project: 106/06/P239
Agency: Czech Science Foundation
Duration: 01. 01. 2006 - 31. 12. 2008

The nature of the crack tip singularity changes in the vicinity of a corner point where a crack front intersects a free surface. Due to the fact, crack propagation in 3D-structures cannot be generally reduced to a series of plane problems along the crack front edge and corner point singularities have to be taken into the consideration. There are two types of stress singularity (the edge and the corner stress singularity) and both influence the fatigue crack propagation behaviour. Suggested project solves this problem on the base of linear elastic fracture mechanics. The fatigue crack is described by the generalised stress intensity factor. Presumptive results make it possible quantitative description of crack propagation rate for crack influenced by the free surface. The numerical analysis is performed by finite element method. The result makes an estimation of residual fatiguelife of 3D-structures more believable.

Majer, Z., Hutař, P., Náhlík, L., Knésl, Z., Influence of particle-matrix interphase on stress distribution in particulate composite with polymer matrix, Applied and Computational Mechanics, Vol.1, 143-148, 2007

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

Knésl, Z., Hutař,P., Seitl, S.: Constraint aspects of the evaluation of fatigue test results in Paris region, Communication 2006, Volume 4: pp. 25-28.

Náhlík, L., Hutař, P., Knésl, Z., Transverse cracking of layered structures: evaluation of fatigue crack propagation, Materials Science Forum, Vols. 567-568, pp. 221-224, 2008

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. 567-568, pp. 225-228, 2008

Hutař, P., Knésl, Z., Relation between constraint and fatigue crack growth rate, Fatigue 2006, Atlanta, 2006.

Hutař, P., Seitl, S., Knésl, Z., Effect of constraint on fatigue crack propagation near threshold in medium carbon steel, Computational materials Science, Vol. 37, 51-57, 2006.

Hutař, P., Sauzay, M., Simulation of fatigue crack growth by crack tip blunting, 16th European Conference of Fracture, Alexandroupolis, Greece, 2006.

Hutař, P., Náhlík, L., Knésl, Z., Numerical investigations of corner singularities in cracked bodies, Key Engineering Materials, Vols. 348-349, 377-380, 2007

Hutař P., Náhlík L., Fatigue crack shape prediction based on vertex singularity, Applied and Computational Mechanics, Vol. 2, No.1, 45-52, 2008

Hutař, P., Náhlík, L., Knésl, Z.: Quantification of the influence of vertex singularities on fatigue crack behavior. Computational Materials Science, Volume 45, Issue 3, May 2009, Pages 653-657