Ivan Nedbal
Czech Technical University in Prague
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Publication
Featured researches published by Ivan Nedbal.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2002
Petr Haušild; Ivan Nedbal; Clotilde Berdin; C. Prioul
The aim of this study is to examine the relationship between fracture energy and the ductile area measured on the fracture surface. Instrumented Charpy tests and fracture toughness tests are performed in the transition temperature range, as well as at lower temperatures. Quantitative fractographic analyses of Charpy specimens reveal a certain proportion of ductile fracture even if the Charpy test is conducted at low temperatures, below the transition temperature. The ductile fracture area situated next to the notch is correlated to fracture energy for all temperatures. In the transition temperature range, fracture energy and the ductile area have a large scatter. Since the limiting event in the development of the ductile area is the initiation of cleavage, the maximum principal stress has been computed in different specimens using the finite element method. It has been shown that the propagating ductile crack does not increase the stress level, but does increase the probability of cleavage fracture through an expansion of the plastic volume where weak points can be found.
Materials Science Forum | 2005
Hynek Lauschmann; Filip Siska; Ivan Nedbal
A new concept of counting time at fatigue processes is proposed, aimed to reach fractographic compatibility in cases of different loading sequences. Values of cycle effectivity are summarized to give the new reference time. The improvement is shown in application - textural fractography of three specimens loaded by constant cycle, constant cycle with periodic overloading, and a random block, respectively. In contrast to the conventional crack growth rate, the reference crack growth rate is related to common morphologic features of all fracture surfaces.
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing | 2003
M. Karlik; Ivan Nedbal; Jan Siegl
International Journal of Fatigue | 2009
Jan Siegl; Ivan Nedbal; Jiří Kunz
Image Analysis & Stereology | 2011
Hynek Lauschmann; Ivan Nedbal
Fatigue & Fracture of Engineering Materials & Structures | 2008
Ivan Nedbal; Hynek Lauschmann; Jan Siegl; Jiří Kunz
Materials Characterization | 2006
Hynek Lauschmann; Jan Siegl; Jiří Šumbera; Filip Šiška; Ivan Nedbal
Journal of Alloys and Compounds | 2004
M. Karlik; Ivan Nedbal; Jan Siegl; J. Prahl
Jsme International Journal Series A-solid Mechanics and Material Engineering | 2002
Bohumír Strnadel; Ivan Nedbal; C. Prioul; Masaki Shiratori
Acta Metallurgica Slovaca - Conference | 2013
Jan Siegl; Ivan Nedbal; Jiří Janovec; Pavlína Hájková; Jan Kober