tailieunhanh - ADVANCES IN COMPOSITE MATERIALS FOR MEDICINE AND NANOTECHNOLOGY_2

Due to their good mechanical characteristics in terms of stiffness and strength coupled with mass-saving advantage and other attractive physico-chemical properties, composite materials are successfully used in medicine and nanotechnology fields. To this end, the chapters composing the book have been divided into the following sections: medicine, dental and pharmaceutical applications; nanocomposites for energy efficiency; characterization and fabrication, all of which provide an invaluable overview of this fascinating subject area. . | Part 3 Characterization and Fabrication 14 Strength Prediction of Composite Materials from Nano- to Macro-scale Konstantinos I. Tserpes Laboratory of Technology Strength of Materials University of Patras Greece 1. Introduction The primary scope behind composite materials development was to reduce structural weight and cost. Nowadays after more than 30 years of development this scope has been partially achieved through the extensive use of CFRP laminates in aeronautical automotive and marine applications. During these years the evolution of composite materials has being mainly accomplished experimentally the contribution of theoretical modeling although necessary is limited due to the difficulties in stress and failure analyses originating from material complexity. In order to extend the use of composite materials specific structural problems such as the increase in out-of-plane strength of laminated composites and effective joining between composite parts must be resolved. Towards the resolution of these problems textile composites with 3D reinforcement have been proposed and adhesive bonding is being forwarded as an alternative to mechanical fastening. However the understanding of the mechanical performance of textile composites is still evolving while the integrity of adhesively composite bonded joints needs to be improved. In the last decade another area has come to the front in the science of composite materials namely nanocomposites. The spunk for the offset of this area was the discovery of carbon nanotubes and the thereafter findings about their extraordinary mechanical properties. Since then several works have been reported on the reinforcement of polymers by carbon nanotubes and other nanoparticles. The first findings are very promising however there are many issues such as the strength of the nanotube polymer interface the role of nanotube alignment and the structural defects in nanotubes that must be clarified before nanocomposites are set to production.