Advanced armour materials and novel materials for impact loading.

: (Alternative Format Thesis)

Abstract

Percussive actions appear in a wide range of forms around us, and so do their effects. In an engineering context, these actions are typically impacts of objects colliding at various velocities, composed of various materials, and affecting both the striker and the target in diverse ways. This thesis presents the development and application of a non-Newtonian polymer designed for superior impact protection, with significant advancements in both composite materials and acoustic applications. The research addresses the growing demand for advanced materials capable of providing enhanced protection and functionality in various engineering sectors. At the core of this thesis lies the development and formulation of a non-Newtonian polymer with rate-dependent, energy-absorption characteristics. This polymer was extensively characterised and tailored to meet the needs of specific applications, demonstrating a unique ability to offer superior impact resistance compared to conventional materials, through an autonomous phase transition process. The original contribution of this thesis is the systematic presentation of different implementations of the non-Newtonian polymer in two engineering fields; impact protection of composite structures, and acoustics. In terms of impact protection of composite structures, four different solutions are offered; a multilayered smart layer which can be retrofitted onto a composite laminate and in a position to avert the detrimental effects of impacts, a hybrid epoxy resin matrix that offers improved impact resistance without affecting the excellent properties of composite laminates, a modified polyurethane core for sandwich composite panels with increased survivability post-impact events, and finally, matrix on a lamina with improved on-demand impact characteristics and structural health monitoring functionalities. The field of acoustics might not seem immediately relatable to that of impact protection. However, a sound pressure wave can be considered a form of a percussive action when contacting a sound insulating material. In this context, membranes tailored to provide dynamic sound attenuation in the low frequency range were investigated initially, followed by an on-demand activation of their excellent sound absorption capabilities. The findings of these research activities pave the way for additional optimisation and exploration of new applications and fields, including advanced sectors such as aerospace and automotive, personal protective equipment, and advanced acoustic solutions.

Date of Award	13 Nov 2024
Original language	English
Awarding Institution	University of Bath
Supervisor	Fulvio Pinto (Supervisor) & Maciek Kopec (Supervisor)