Characterization of Carbon Fiber Composite Materials behaviour through experimental tests and analytical analyses

The more and more urgent need of cost and weight reduction for the new generation aircrafts has produced a wide research activity on new materials that could guarantee low weights and high safety levels. These goals will also be able to decrease fuel consumption and thus they could have a beneficial effect on pollution reduction too. Among them, composite materials could offer a solution to these items thanks to the mechanical properties that can be obtained and the possibility of producing highly integrated components. It is well-known that composite multi-layer properties change in connection with plies distribution. Moreover, they are affected by large scatters, so these composite properties must be well characterized only by means of wide testing activities. In addition, impacts and exposure to hot/wet environmental conditions can degrade their behaviour during their life, sometimes without any evident warning signs. This paper shows a testing activity which has been carried out at the Department of Aerospace Engineering of Pisa on carbon fibre composite materials to characterize different materials and structural solutions and to evaluate the effect of environmental conditions on their mechanical properties. So, a large amount of simple specimens has been tested, including un-notched specimens, open hole specimens and filled hole specimens, subjected to tensile and compressive static loads, in monolithic and sandwich configurations. In addition, some FEM simulations have been made and the comparison with the experimental results is also shown.