S25  Métodos Numéricos    Titulo: BOUNDS FOR THE EFFECTIVE CONDUCTIVITY OF UNIDIRECTIONAL COMPOSITES BASED ON ISOTROPIC MICROSCALE MODELS   Resumo : THE NUMERICAL STUDY OF HEAT CONDUCTION IN COMPOSITE MATERIALS IS MUCH ADVERSELY AFFECTED BY THE GEOMETRICAL STIFFNESS ARISING FROM THEIR GENERALLY COMPLEX MICROSTRUCTURES, PARTICULARLY AT HIGH CONCENTRATIONS. WITH THE PURPOSE OF ALLEVIATING THE CONSEQUENCES OF GEOMETRICAL STIFFNESS, IN THIS PAPER WE DEVELOP BOUNDS FOR THE EFFECTIVE CONDUCTIVITY OF UNIDIRECTIONAL COMPOSITES WITH A THERMALLY-CONDUCTING DISPERSED PHASE, BASED ON SIMPLE ISOTROPIC MICROSCALE MODELS. OUR APPROACH PROCEEDS BY AN INNER-OUTER DECOMPOSITION, IN WHICH ANALYTICAL APPROXIMATIONS AT THE MICROSCALE ARE FOLDED INTO MODIFIED OUTER PROBLEMS DEFINED OVER GEOMETRICALLY MORE HOMOGENEOUS DOMAINS. RIGOROUS LOWER AND UPPER BOUNDS FOR THE EFFECTIVE CONDUCTIVITY ARE THEN DEFINED BASED ON THE SOLUTIONS OF THESE OUTER PROBLEMS. THE BOUNDS ARE MOTIVATED PHISICALLY AND PROVEN MATHEMATICALLY, BY USING CLASSICAL VARIATIONAL SPACE RESTRICTION AND EMBEDDING ARGUMENTS. THE FORMULATION IS APPLICABLE TO BOTH ORDERED AND RANDOM FIBROUS COMPOSITES, AND IT IS EASILY EXTENDABLE TO THREE-DIMENSIONAL PARTICULATE COMPOSITES.     Autores : Cruz, Manuel Ernani Carvalho Machado, Leandro Bastos     Trabalho Completo :   COBEM99 | Comissão  Organizadora | Palestras | Sessões Técnicas | Autor | Simpósios e Sessões Especiais | Revisores |  Título  dos  Trabalhos | Local