Fatigue behaviour of composites - Padua@Thesis
This work is the product of almost six months spent at University College Dublin. It consists on
fatigue tests done in CFRPs with and without steel fibres inside. The idea of insert a different fibre
material layer inside CFRPs is proposed to improve fracture toughness and especially delamination
behaviour that is one of the mechanism that brings to failure.
These material samples were tested statically in a previous research project and the team at UCD
was interested in testing them also under fatigue solicitation to compare results and behaviours.
CFRP is studied because can be applied in aerospace and automotive field so there is a lot of
interest in discovering how it behaves in particular under a cyclic force. After a first fatigue test,
samples were tested again in fatigue to see how they replied to a second cyclic load. Repeating
fatigue tests is a study of big interest nowadays because it can bring to a better material’s
characterisation and it can simulate a real phenomenon which happens during material’s life. In
order to do experiments, standards and rules are necessary to regulate procedures and obtain proper
results. From data analysis it is possible to see that, as happened in static tests, fibres improve
material’s behaviour and increase fracture toughness. As future work, it is suggested to continue the
investigation of fatigue in these materials, especially to work on repeating fatigue tests because it is
necessary to find new standards in order to better describe and understand how samples react to
solicitation.
This work is the product of almost six months spent at University College Dublin. It consists on
fatigue tests done in CFRPs with and without steel fibres inside. The idea of insert a different fibre
material layer inside CFRPs is proposed to improve fracture toughness and especially delamination
behaviour that is one of the mechanism that brings to failure.
These material samples were tested statically in a previous research project and the team at UCD
was interested in testing them also under fatigue solicitation to compare results and behaviours.
CFRP is studied because can be applied in aerospace and automotive field so there is a lot of
interest in discovering how it behaves in particular under a cyclic force. After a first fatigue test,
samples were tested again in fatigue to see how they replied to a second cyclic load. Repeating
fatigue tests is a study of big interest nowadays because it can bring to a better material’s
characterisation and it can simulate a real phenomenon which happens during material’s life. In
order to do experiments, standards and rules are necessary to regulate procedures and obtain proper
results. From data analysis it is possible to see that, as happened in static tests, fibres improve
material’s behaviour and increase fracture toughness. As future work, it is suggested to continue the
investigation of fatigue in these materials, especially to work on repeating fatigue tests because it is
necessary to find new standards in order to better describe and understand how samples react to
solicitation.
