Mwcnt-modified fiber reinforced composites with nano-sensing capabilities: a way towards the development of the new functional materials for space applications

Paper number

IAC-06-C2.8.03

Author

Mr. Antonios Vavouliotis, University of Patras, Greece

Coauthor

Dr. Panagiota Tsotra, Greece

Coauthor

Prof. Vassilis Kostopoulos, University of Patras, Greece

Coauthor

Mr. Petros Karapappas, University of Patras, Greece

Coauthor

Mr. Angelos Miaris, University of Patras, Greece

Coauthor

Mr. Nikolaos Nikolaou, University of Patras, Greece

Year

2006

Abstract

Multi-functionality is an aspect that space technology is focusing on the last decades. Space systems design parameters like the mass reduction with increased system efficiency demand multifunctional approaches. The technology concept of multifunctional materials with sensing capabilities combined with enhanced mechanical properties could prove useful for the high requirements of the space sector. Composite materials are nowadays widely used in space applications. The introduction of nanotechnology in the field of composites has opened new horizons towards the development of advanced materials with unique functional properties. The incorporation of nano-fillers like carbon-nanotubes (CNTs) in conventional carbon fiber reinforced polymers (CFRPs) introduces the possibility of improved electrical and thermal properties combined with high mechanical efficiency. Moreover, the non-destructive damage detection in CFRPs during mechanical loading is a key parameter in many applications, especially in space structures. Previous studies within the last decade have shown that the mechanical deformation and the electric resistance of CFRPs are closely connected, so that the material can act as an inherent sensor of its own damage. 
The target of this research is to set a point about the control of the damage growth and propagation via the monitoring of the electrical conductivity during mechanical loading of CFRPs. Towards this direction, multi-walled carbon nanotubes (MWCNTs) were used as an electrically conductive dopant in the polymeric matrix. The doped resin compounds were produced using a vacuum dissolver under controlled temperature. Doped resin compounds with different MWCNT contents were produced. Afterwards CFRPs with the above resins as matrix material were manufactured. The carbon fibre (CF) laminas were chosen to be unidirectional (UD) by Kohlegewebe (Germany) with weight of 140 gr/m2. Each panel had 16 plies of carbon laminas and was hand laid-up and then processed in an autoclave, using the vacuum bag technique. 
Specimens were subjected to increasingly loading-unloading-reloading tension tests and the resistance was measured at the maximum loading and at the unloading position of each loading cycle. Significant changes can be noted in the resistance of the doped specimen. With increasing applied load the resistance increases due to the damage of the fibers and the resulting progressive damage of the percolating network. During the unloading phase of the specimen the broken fibers and the cracked percolation net are forced to come in contact and consequently the resistance decreases slightly. 

Abstract document

IAC-06-C2.8.03.pdf

Manuscript document

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