In the present paper, experimental investigations were conducted to assess the effect of nanomodification on the impact behaviours of hybrid composite plates. Graphene nanoplatelets (GNPs) of two different sizes, 5 and 30 µm, were used to modify a composite material made with 64 wt.% of unidirectional fibres and a low-viscosity epoxy resin. The effect of the nanomodification with 30 µm GNPs was also studied on composite plates prepared with a higher viscosity resin. Three laminate thicknesses (4, 8, and 16 layers) were tested with a standard drop dart testing technique. The peak forces as well as the absorbed energy and the fracture surfaces, observed with a Scanning Electron Microscope (SEM), were compared. Experimental results showed that nano-modification with 5 µm particles had a detrimental effect on both the peak forces and the absorbed energy, whereas the addition of 30 µm GNPs increased the absorbed energy, especially for a laminate thickness of 16 layers. Overall, the experimental results demonstrated that the size of graphene nanoparticles has a significant effect on the impact response of composite laminates.

Battery failures are obvious after being subject to abuse conditions however predicting these failures in advance is crucial when using test and validation techniques to understand battery potential. Lithium-ion battery cells are widely used due to their high energy and power densities. When abusive conditions like the three point bend loading are applied to lithium-ion batteries, what occurs to the mechanical behaviours and components is still mostly unknown. To further this understanding, this paper investigates the mechanical behaviour of the separator in the LiCoO2/Graphite cylindrical 18650 cells. Internal short circuit (ISC) behaviour, strain rate dependency and electrochemical status of the cells (i.e. SOC dependency) are studied to understand failure pattern. Furthermore, simple and effective constitutive model for the separator layer is formed, facilitating further mechanical analysis and numerical simulation of lithium-ion battery study. Occurrence of ISC is investigated by jellyroll deformation where casing is removed, and quasi-static load is applied. Numerical simulation model is developed to further investigate sequential structural failures and temperature changes. Simulation results showed good accuracy with experimental results and are useful to predict structural failure of cells. Number of failures including electrolyte leakage, change in shape, sudden voltage drop/temperature rise, and gas venting are observed.

Within this paper methods in reducing weight and optimizing the front-end structure, by specifically targeting both new materials and redesigning the cashbox, to improve crashworthiness were investigated. This was accomplished through redesigning the cross-sectional shape of the crash box, trigger location and type of trigger used, and the use of different materials. The optimal crash box design was found to be a hexagonal prism that incorporated a central trigger which reduced the thickness from 2mm to 1mm. Moreover, the ideal material was identified to be SGF/PA6/GnPls. When this optimized crash box was incorporated to the front-end structure and the ideal material applied to the bumper beam, the fully optimized front-end structure reduced the weight by 75%, reduced peak force by 28% and increased specific energy absorption by 94% and 55% for a frontal and side collision respectively.

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