Abstract:
Aims: Relatively poor mechanical properties of conventional hydrogels can considerably be improved by adding a stiff and brittle network into a soft and flexible polymer. The aim of the present contribution is to develop a constitutive model for so synthesized double network hydrogels. Of special interest is the multiaxial damage cross-effect which should also be taken into account.
Methods: We consider a somewhat complex interplay of both networks and propose a micromechanical model of double network hydrogels. Accordingly, the directional fracture of the first network results from cumulative damage in all directions. The model is based on an analytical network-averaging concept which generalizes a onedimensional chain model to the three dimensions without numerical integration.
Results: The proposed analytical model includes very few physically motivated material parameters and demonstrates good agreement with comprehensive multidirectional experimental data.
Conclusions: The proposed model forms a solid basis to further study various multiphysical effects in double-network hydrogels and in particular swelling.

Biography: Prof. Itskov got his Diploma Degree in Automobile Engineering at the Moscow State Automobile and Road Technical University (TU MADI) in 1987. In 1990 he got Doctor Degree in Mechanics at this Technical University. In 1995 he came to Germany as a fellow of the German Academic Exchange Service (DAAD) and worked later as a research assistant at the Ruhr-University of Bochum and then at the University of Bayreuth. In 2002 he got his Habilitation degree in Mechanics. Since 2004 he is full professor of continuum mechanics at the faculty of Mechanical Engineering of the RWTH Aachen University. Prof. Itskov is author of the book “Tensor Algebra and Tensor Analysis for Engineers” whose 5th edi-tion appeared recently and of many publications in international peer-reviewed journals. Research interests of Prof. Itskov are mechanics of soft materials like rubbers, hydrogels, soft biological tissues and modelling of anisotropic material under large strains.