%0 Book Section
%A Paggi, Marco
%A Wriggers, Peter
%B Computational plasticity XI : fundamentals and applications
%D 2011
%F eprints:2072
%I International center for numerical methods in engineering (CIMNE)
%K Hierarchical materials; Polycrystalline materials; Imperfect interfaces; Cohesive zone models; Finite element method
%P 1082-1090
%T Stiffness and strength of hierarchical polycrystalline materials with imperfect interfaces
%U http://eprints.imtlucca.it/2072/
%X In this paper, considering a cohesive zone model (CZM) for finite thickness  interfaces recently proposed by the authors, the stiffness of polycrystalline materials with  imperfect interfaces is characterized. Generalized expressions for the Voigt and Reuss  estimates of the effective elastic modulus of the composite are derived to interpret the  numerical results. Considering a polycrystalline material with a hierarchical microstructure,  the interaction between interfaces at the different hierarchical levels is numerically  investigated. A condition for scale separation, which suggests how to design the optimal  microstructure to maximize the material tensile strength is determined. An original interpretation  of this phenomenon based on the concept of flaw tolerance is finally proposed.
%Z Volumen containing the full length papers accepted for presentation at the  XI International Conference on Computational Plasticity.  Fundamentals and Applications  Barcelona, Spain, 07-09 September 2011