报告摘要：
Theoretical basis for nonlinear fracture mechanics parameters has been discussed, starting from the conservation law of J integral type and ending beyond the limits of static loading, plane 2D problem and homogeneous material. Twofold meaning of J integral, one as crack driving force, and the other, as material crack resistance, has been employeed to apply fracture mechanics basic concept to assess structural integrity of different critical components, like welded joints in pressure vessels, biomaterials for hip replacement and aeronautical structures. Numerical simulation by the non-linear Finite Element Method is used to calculate crack driving forces, whereas standard and non-standard experimental evaluation is used for material testing. Some specific aspects of this approach has been discussed, including the fact that even in the case of static loading, numerical simulation is not a simple task because of complex geometries and material non-linearity and heterogeneity, whereas lack of material often makes expereimental procedures tedious. Finally, micromechanical modelling of elastic-plastic crack growth is presented as new an promising approach to overcome some of the shoratges of traditional approach.
Besides static loading, couple of other important practical problems are tackled, like fatigue and creep crack growth. In both cases remaing life is the focus of investigation, using the empirical laws for crack growth rates. Numerical simulations for both fatigue and creep crack growth are inherently complex both due to complex material damage processes and lack of sound theoretical basis to define them. Anyhow, combination of theoretical, experimental and numerical approach is presented which has enabled reliable and efficent estimation of life even for such a complex problems.
报告人简介：
Aleksandar Sedmak, Professor (from 2001) at the University of Belgrade, Faculty of Mechanical Engineering, Department for Materials technology. Ph.D. thesis (Conservation law of J intregral type for thin shells) – University of Belgrade, 1988. Director of Innovation Centre of the Faculty of Mechanical Engineering (from 2007). Assistant Minister - Head of Sector for Technology Development and Innovation System, Serbian Government (2003-2006), Vice-Rector of University of Belgrade for the international cooperation (2006-2009). Visiting professor Drexel University, USA (1999-2002). Published 102 papers in scientific journals (ISI), more than 750 publications totally, including the European and International Fracture conferences. Full member of Serbian Academy of Engineering Sciences since 2012. Vice president of European Structural Integrity Society (ESIS) since 2014, President of Serbian Structural Integrity Society since 2008, editor-in-chief - Int. Journal on Structural Integrity and Life. Main topics of interest: Fracture Mechanics, Structural Integrity, Computational Mechanics, Materials Science, Welding and Welded Structures. The chairman of European Conference on Fracture in Belgrade, 26-31 August 2018.
