Compósitos poliméricos reforçados com fibras de carbono (CFRP) incorporando fios atuadores de NiTi com memória de forma: caracterização termomecânica usando análise mecânica dinâmica (DMA).

Abstract

Active structures can be obtained by incorporation of wires with shape memory effect (SME) embedded into a metal or polymeric matrix. However, have been found that polymeric matrices present better results in a wide range of applications for this kind of purposes. Nevertheless, composites obtained from shape memory alloys (SMA) and polymeric matrix in spite of exhibiting an excellent activation potential do not show high mechanical properties, an example of this is a tensile modulus below 10 GPa. Recent studies are attempting to show the possibility of obtaining an active composite with improved mechanical properties through the introduction of SMA into an epoxy matrix, as carbon fibers (CFRP) as well glass fibers (GFRP). In this context, the aim of the present study is develop a methodology for manufacture CFRP NiTi samples to characterize thermomechanical and dynamic mechanical detail by applying the technique of dynamic mechanical analysis (DMA), thus evaluating the activation potential of composite (CFRP) containing Ni-Ti SMA wires embedded. Therefore, an initial analysis to characterize the constituents expected to be used and then through the possible dimensions for analysis in DMA has developed a methodology for obtaining samples of CFRP NiTi potentially active. Initially we used fiber matrix CFRP completely aligned, thereby providing a composite with high mechanical properties (elastic modulus and damping) and there is then the need for use of a matrix with lower elastic modulus, thus made by an analysis of the modulus variation for a pre-embedded (CFRP) aeronautic according to the disposition angle of the carbon fibers in order to determinate the more adequate matrix for introducing Ni-Ti SMA wires (elastic modulus of CFRP very close to Ni-Ti wires in martensitic state) to obtain active composite Results of elastic modulus vs. temperature obtained by Dynamic Mechanical Analyzer (DMA) at different mechanical loadings showed that the matrix (CFRP) with fibers oriented at an angle of 15° has enormous possibilities to obtaining composites potentially active, beside of providing higher mechanical properties than those produced with pure polymeric matrices also present an increase in the elastic modulus and damping capacity considerable, from heating the CFRP-NiTi system.