Processability of Bindered Dry-Fibre Tapes in Ultrasonic Spot Welding and Double Diaphragm Forming for High-Volume Manufacturing

<p dir="ltr">This thesis addresses the growing demand for reliable, cost-efficient carbon fibre composite manufacturing by investigating automated preforming of unidirectional bindered dry-fibre tapes. Ultrasonic Spot Welding was validated as a fast, repeatable, low-energy method for tape fixation in automated tape placement, with tape characteristics and processing conditions affecting lap shear strength and preform quality. Double Diaphragm Forming was investigated as a near-net-shape, resource-efficient forming technique, focusing on tape friction, interface behaviour, and bridging mitigation. Collectively, these findings provide novel insights into material selection and forming optimisation, supporting high-volume sequential dry-fibre tape preforming for lightweight aerospace and automotive structures.</p>