Co-investigator: Ing. Stanislav Seitl, Ph.D.
Number of Project: 101/08/1623
Agency: Czech Science Foundation
Duration: 01. 01. 2008 - 31. 12. 2009

The project comprises an improving of computational techniques for assesment of residual life of bodies with fatigue cracks with respect to the influence of following factors: geometry of a body, corner stress singularity, roughness of fracture surfaces, bi-material interface, in-plane and out-of-plane constraint and local low-cycle plastic and fracture properties of material. Input data for 2D and 3D FE models will be obtained from fatigue crack experiments in threshold area and low-cycle fatigue experiments. The distribution of the T-stress slony the crack front and stress singularity change near the free surface and bi-material interface influence on crack behavior will be studied using FE computations. The results will be applied to crack front shape and rate prediction in bodies with complicated geometry and material composition. Nonlinear elastic-plastic FE models will be used for fatigue crack growth prediction based on local fracture criteria for microscopic low-cycle fatigue. The energetic criterion and criteria of Manson-Coffin and Smith-Watson-Topper type will be tested.

Majer Z., Hutař P., Náhlík L., Knésl Z. The influence of loading direction on micro-crack behaviour in polymer composite, Applied and Computational Mechanics, Vol. 2, No. 2, 285-290, 2008

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