A new method for characterising the rate-dependent failure of elasto-plastic adhesively bonded structures has been developed and used to investigate the different modes of loading of representative interfaces. Furthermore, experimental observations enabled a newly developed cohesive zone model that captures all critical aspects of the observed and quantified behaviour of the adhesive under consideration. In particular, the model is capable of reproducing the conducted experiments by incorporating both the dependence of the deformation rate and the adhesive thickness. For that, computed tomography of the adhesive interface was used to resolve three-dimensionally the adhesive volume. The volume fraction of microscopic voids in the adhesive was introduced into the model to rationalise the observed dependence of the mechanical response of the adhesive upon its thickness. Finally, the cohesive zone model was proven with mixed-mode fracture experiments which demonstrate the model's ability to simulate more complex deformation regimes.

Fracture mechanics experiments are used to investigate the rate-dependent failure of adhesively bonded structures under different deformation modes: I, II and I/II. First, the high-rate mechanical response of the adhesive interface is analysed with a newly developed method -which relies entirely upon digital image correlation. The method was purposely designed to avoid any dynamic effects which may be present. This novel method is verified against quasi-static standard methods showing good agreement. Finally, simulations of the experiments are used to validate a cohesive zone model of the adhesive. The ability of the model to predict cohesive failure under a wide range of strain rates and deformation modes is demonstrated.

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The increasing use of adhesive joints in dynamic applications require reliable measurements of the rate-dependent stress-displacement behaviour. The direct measurement of the stress-displacement curve is necessary when using cohesive models in discretised solutions of boundary value problems in solid mechanics. This paper aims to investigate the rate-dependent tensile failure of adhesive joints by using a new experimental methodology-it relies upon the combination of the stress wave propagation theory and digital image correlation methods on high speed footage to quantify the tensile stress and the dissipated energy respectively. For this purpose, the Split Hopkinson Bar methodology was employed-the experimental configuration was optimised using numerical modelling. To prove the sensitivity of our framework, two different adhesives are characterised at different loading rates: the adhesive failure strength was found to increase considerably with the strain rate, while the plastic deformation of these adhesives was reduced. The film adhesive showed superior performance over the particle toughened one. In the final part, a rate-dependent cohesive zone model is proposed, one which captures the measured behaviour and which has the potential to be used in industrial applications.

Electrospinning technique is well-known for the generation of different fibers. While it is a "simple" technique, it lies in the fact that the fibers are typically produced in the form of densely packed two-dimensional (2D) mats with limited thickness, shape, and porosity. The highly demanded threedimensional (3D) fiber assemblies have been explored by timeconsuming postprocessing and/or complex setup modifications. Here, we use a classic electrospinning setup to directly produce 3D fiber macrostructures only by modulating the spinning solution. Increasing solution conductivity modifies electrodynamic jet behavior and fiber assembling process; both are observed in situ using a high-speed camera. More viscous solutions render thicker fibers that own enhanced mechanical stiffness as examined by finite element analysis. We reveal the correlation between the universal solution parameters and the dimensionality of fiber assemblies, thereof, enlightening the design of more "3D spinnable" solutions that are compatible with any commercial electrospinning equipment. After a calcination step, ultralightweight ceramic fiber assemblies are generated. These inexpensive materials can clean up exceptionally large fractions of oil spillages and provide high-performance thermal insulation. This work would drive the development and scale-up production of next-generation 3D fiber materials for engineering, biomedical, and environmental applications.

Ethylene-Vinyl Acetate (EVA) is the most popular material for manufacturing mouthguards. However, EVA mouthguards are problematic, for example inconsistent thicknesses across the mouthguard. Additive manufacturing provides a promising solution to this problem, as it can manufacture mouthguards with a greater precision. This paper compares the energy dissipation of EVA, the current material used for mouthguards, to various designs of a 3D printed material, some of which contain air cells. Impact testing was carried out at three different strain rates. The Split-Hopkinson bar was used for medium and high strain rate tests, and an Instron test rig was used for low strain rate testing. The best performing design dissipated 25% more energy than EVA in the medium and high strain rate testing respectively while the low strain rate testing was inconclusive. This research has shown that additive manufacturing provides a viable method of manufacturing mouthguards. This opens up the opportunity for embedding electronics/sensors into additive manufactured mouthguards.

The rate-dependent failure response of multi-material adhesive joints for three deformation modes is investigated. A combination of carbon fibre reinforced polymers (CFRP) and titanium alloy Ti-6Al-4V is employed. The experiments provide important information about the failure sequence of a multi-material adhesive joints, which depends upon the loading rate regime. This is the first time that dynamic fracture mechanics experiments are performed in multi-material adhesive structures. The observed experimental results suggest a rate-dependent failure sequence for mode I dominated fracture. Simulations of the experiments are used to predict and rationalise the failure performance of the multi-material adhesive joint. The numerical analysis highlighted the importance of the individual knowledge of the rate-dependent mechanical performance of adhesive and composite to fully understand the fracture sequence of multi-material joints under impact.

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