Investigator: Ing. Vladislav Kozák, CSc.
Number of Project: GA101/00/0170
Agency: Czech Science Foundation
Duration: 01. 01. 2000 - 31. 12. 2002

The purpose of the project is to evaluate the brittle and ductile fracture of components with cracks and the stress concentrators with respect to transition behavior on the micromechanistics deterministic and stochastic models of failure. The experimental data from laboratory and finite elements method are the base tools. The principle of this project is measurement of a fracture toughness on the „small specimens“. The project concludes with an application of the mentioned models to predict the material behavior on the standard geometry and components and structures. The solution of this project concurs of the project results of the grant of the Grant Agency of the Czech Republic „Local approach for the assessment for brittle fracture of components” and running project NATO SfP „Fracture resistance of steels for containers of spent nuclear fuel No. 972655“. The goal is to examine and develop „fracture toughness scaling models“ based on the micromechanistics treatment to predict constraint and size effects on cleavage fracture toughness. General approaches adopt e. g. the Weibull stress w as a suitable near crack-tip parameter to evaluate the statistics of microcracks, in another models e.g. the critical size of plastic zone is used, etc. The manganese cast steel intended for the container of the spent nuclear fuel Škoda will be used as a investigated material. For verification of various models, the rotor steel which can be prepared in some modification for various micromechanisms of fracture, will be also used.

B. Strnadel, I. Dlouhý: Probability of Brittle Fracture in Low Alloy Steels; Transferability of Fracture Mechanical Characteristics, 2002, Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 151-166.

L. Jurášek, J. Kohout, M. Holzmann, I. Dlouhý: Statistické a fyzikální aspekty použití koncepce master křivky při hodnocení vlivu rychosti zatěžování na tranzitní chování ocelí; Sborník příspěvků semináře: Únava a lomová mechanika 2002, Metodické a aplikační problémy, Žinkovy, Česká republika, 2002.

M. Holzmann, L. Jurášek, I. Dlouhý: Master Curve Methodology and Data Trensfer from Small on Standard Specimens; Transferability of Fracture Mechanical Characteristics, I. Dlouhy Ed., 2002, Kluwer Academic Publishers, Dordrecht, Netherlands, pp. 225-242.

V. Kozák, I. Dlouhý: Weibull stress model in cleavage fracture and toughness scaling model; XXX Summer School "Advanced Problems in Mechanics", St. Petersburg (Repino), Russia, 2002 (sborník 2003), pp. 384-389.

V. Kozák, I. Dlouhý, M. Holzmann: The fracture behaviour and its predicion based on the local approach; Nuclear Eng. And Design, č. 212, 2002, pp. 67-73.

V. Kozák, I. Dlouhý: The transferability of fracture toughness characteristics from point a view of the integrity of components with defects; Computational Methods and Experimental Measurements (CMEM 2001), Alicante, Španělsko, 2001, pp. 757-766.

V. Kozák, M. Holzmann, I. Dlouhý: The Transferability of Brittle Fracture Toughness Characteristics; Structural Mechanics in Reactor Technology; SMIRT 16, Washington, DC, 2001, Proc. on CD (Paper#1079).