A main weakness of fibre reinforced thermoset polymers is their low interlaminar strength, which makes them susceptible to delamination under impact load. The introduction of composites in other transport sectors, like the automotive, naval and railways, for which the lightness is not an imperative as in airplane, has driven the research interest towards the use of thermoplastic matrices. The latter are characterized by higher damage tolerance and interlaminar toughness, which is due to the presence of the amorphous phase which can limit the crack propagation and allow larger deformations. They also show advantages over the thermoset ones in terms of potential recyclability after life-cycle, reprocessing, faster production processes, chemical and environmental resistance, reduced moisture absorption and, usually, reduced costs. Among thermoplastic matrices, polypropylene (PP) is considered one of the most promising because of its low density, good processability and environmental resistance. In addition, a good-to-impact performance material can be tailored by managing the interface strength. The attention of the present work is devoted towards the behaviour to low velocity/energy impact load of polypropylene based laminates reinforced with glass fibres with a change of interface strength. The different material behaviour is assessed through monitoring online of the impact event and through nondestructive evaluation with lockin thermography.
Infrared thermography to evaluate impact damaging of thermoplastic composites
P Russo
2014
Abstract
A main weakness of fibre reinforced thermoset polymers is their low interlaminar strength, which makes them susceptible to delamination under impact load. The introduction of composites in other transport sectors, like the automotive, naval and railways, for which the lightness is not an imperative as in airplane, has driven the research interest towards the use of thermoplastic matrices. The latter are characterized by higher damage tolerance and interlaminar toughness, which is due to the presence of the amorphous phase which can limit the crack propagation and allow larger deformations. They also show advantages over the thermoset ones in terms of potential recyclability after life-cycle, reprocessing, faster production processes, chemical and environmental resistance, reduced moisture absorption and, usually, reduced costs. Among thermoplastic matrices, polypropylene (PP) is considered one of the most promising because of its low density, good processability and environmental resistance. In addition, a good-to-impact performance material can be tailored by managing the interface strength. The attention of the present work is devoted towards the behaviour to low velocity/energy impact load of polypropylene based laminates reinforced with glass fibres with a change of interface strength. The different material behaviour is assessed through monitoring online of the impact event and through nondestructive evaluation with lockin thermography.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
