Linear Bending Behaviour of Functionally Graded Polymer Composite Beams Reinforced with Graphene Nanoplatelets

Graphene is an amazing and relatively newly discovered material that has been shown to exhibit excellent mechanical properties. These properties have been proven to increase the strength of polymer structural members through various research over the past ten to fifteen years. Functional graded materials have also been shown to provide an effective way of increasing the mechanical capacity of members. Through a review of available literature, it is evident that there has been minimal research into functionally graded epoxy composite beams reinforced with Graphene nanoplatelets (GPLs). The majority of the research focused on composite plates using numerical methods. These studies also focused on GPL volume fractions varying across the thickness of the material (unidirectional GPL distribution). The research presented in this dissertation studied the bending behaviour of functionally graded polymer composite beams reinforced with graphene nanoplatelets (GPLs). Strand7 was to analyse beams with multiple support conditions to determine the changes in deflections and stresses. The literature review in Chapter 2, provides background information on each of the materials and components used within the beam models, as well as details on calculating the functionally graded distribution of the GPLs across the thickness using a linear distribution about the neutral axis. The details of the methodology are presented in Chapter 3. In Chapter 4, a validation study is presented. To ensure the validity of the Strand7 models used within the research of this dissertation, the results of unidirectional GPL distribution beam models were compared with previous research by Feng et al. (2017) and plate models in Strand7. The results showed good agreement, which provided validation of the models. In Chapters 5 and 6, studies were completed on various methods of bidirectional functional grading. Chapter 6 specifically focused on creating a simpler method of bidirectional GPL distribution in order to provide a method for easier and less costly laboratory tests, compared with a truly bidirectional FG beam. The main conclusion of this study is that by providing functional grading of the GPL reinforced polymer composite that mimics the von Mises stresses (VM method), the beams bending stiffness can be increased. Due to current manufacturing technology limitations, a simplified GPL distribution method is presented that performs nearly as well as the VM method. However, this simplified method provides a way to begin experimental testing