FP6 priority
1.1.3   Nanotechnologies and Nanosciences, Knowledge-based Multifunctional Materials and New Production Processes and Devices
Title of the proposal

Thermal and stress analysis and fracture of functionally graded materials

Slovak Academy of Sciences, Institute of Construction and Architecture
Dubravska cesta 9, 842 20 Bratislava, Slovak Republic
Jan SLADEK, Prof. Ing. DSc.
+421 2 547 88662

Research subject for a potential FP6 project

The use of analytical computational methods is strongly restricted to study of problems with simple geometry and loading conditions. General-purpose numerical methods such as the finite element method (FEM) or the boundary element method (BEM) cannot be used satisfactorily to tackle the problems investigated in FGMs without further development. One of the goals of this project is to extend the advantages of the BEM (as compared with other discretization methods) to its application to solution of boundary value problems with media of FGMs. Beside the stationary also the transient time dependent problems will be considered. Concerning the time variable, various approaches are aimed to be tested. As to the physical nature of considered fields, we shall deal with elastic and thermal fields including their interaction. From the computational point of view, we want to investigate the response of both the primary fields (displacements, temperature...) and their derivatives (stresses, fluxes...). Advanced computational techniques are required especially if the evaluation point is on the boundary or close to the boundary of the domain.Although the stress intensity factor concept is still applicable in FGMs, the region for its evaluation can be decreased substantially by high modulus gradients. The inaccuracy of numerical computation of SIFs is increasing by moving the evaluation point to the crack tip because of the stress singularity. Therefore other advanced numerical techniques based on path independent integrals would be appreciated. The standard J-integral is not any more path-independent in FGMs. We aim to pay attention to modification and/or derivation of new path-independent integrals that could be applied to evaluation of fracture characteristics in FGMs. Using the developed integral equation methods could perform the deformation analysis of cracked bodies.

Recent international cooperation of the research team

University of Applied Sciences, Zittau/Gorlitz, Germany
Institute of physics of materials, Czech Academy of Sciences, Brno

Proposerīs relevant publications related to the research subject

1. J. Sladek, V. Sladek and S.N. Atluri: A pure contour formulation for meshless local boundary integral equation method in thermoelasticity, Computer Modeling in Engineering & Sciences 2 (2001), 423-434.
2. J. Sladek, V. Sladek and M. Hrina: Evaluation of fracture parameters for functionally gradient materials, in: Damage abd Fracture Mechanics VI (A.P.S. Selvadurai and C. A. Brebbia, eds.), WIT Press, Southampton, 2000, pp. 35-44.
3. V. Sladek and J. Sladek (Eds.): Singular Integrals in Boundary Element Methods, CMP, Southampton 1998.