Browsing by Author "Appleby-Thomas, Gareth"

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    Failure modes of CFRP panels under hypervelocity impact: the effects of strain rate between 1 km/s and 6 km/s
    (ASME, 2024-12-31) Lawrence, Jacob; Painter, Jonathan; Iordachescu, Alexandra; Footer, Charles J.; Seabright, Ryan M.; Appleby-Thomas, Gareth
    Studying the effects of hypervelocity impacts on structural materials is essential for the aerospace and defense fields. However, there is a paucity of open-source and accessible data in the literature concerning the hypervelocity impact response of CFRP composites. This paper details our results from an experimental research program designed to aid in addressing this limitation by providing extensive data from multiple analysis techniques. This is part of a wider body of research focused on identifying failure modes and their evolution at elevated strain rates. Experimental work on the impact of commercially available CFRP composites at impact velocities between 1000 and 6000 m/s is presented and discussed. This work provides further validation for the response of an aerospace-relevant material to extreme loading conditions, with wider implications for the design and use of these structures in various industries. Preliminary results from optical imaging, HSV capture, SEM, VP-SEM, and target mass loss analysis are included and show a strain rate dependence in the CFRP material studied.
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    Improving adhesion in bonded ceramics through novel additively manufactured surface geometries
    (Cranfield University Defence and Security, 2024-11-13) Powell, Daniel; Appleby-Thomas, Gareth; Painter, Jonathan
    Many high-value industries (including medical, aerospace, and defence) utilise ceramics for their favourable properties, such as high hardness, low thermal / electrical conductivity, and chemical resistance. The latter property results from chemical inertness. However, this inertness leads to weaker bond strengths when joining ceramics with other materials, as is often required to overcome their brittle nature and low tensile strength.Geometries can be introduced to the surface of a material to act as adhesion promoters through increasing the surface area of the bond, but more interestingly through mechanical interlocking between the ceramic and bonding material. Whilst this would be impossible to achieve through conventional manufacturing techniques, additive manufacturing (AM) can create these novel surface geometries. This work pushes the capabilities of ceramic AM at a scale of no greater than 500 µm, finding the limits of the current technology. Furthermore, the potential for increased bonding through the generated geometries is investigated.