Fatigue Behaviour of Composites under VIbration and Thermal Loading

Abstract

This thesis work examines the fatigue life of composite laminates under vibration fatigue loading and elevated ambient temperature conditions. Thus, the main objective of the current study is to pave the way on the rarely – discussed subject of vibration fatigue of composites under various exposure temperatures. This dissertation will guide the reader through the design of the testing method, which takes into account the environmental conditions while utilising a pre – defined failure criterion. Also, it focuses on the main aspects of the experimental procedure and highlights the common challenges associated with the procedure in order to achieve quality results and improve repeatability. Throughout the chapters, an overview on the accumulation of damage will support both the experimental and numerical investigations, aiming to generate insight regarding the physics that govern the fatigue behaviour of composites. Having identified the distinct stages of the mechanical and thermal responses and the size of fatigue damage accumulated at the respective stages during endurance, the outcomes of the novel testing method are discussed; aiming to link the two responses of composite laminates. The knowledge gathered, about the damage growth and its dependency to ambient thermal loads, is then employed in order to explore more complicated conditions such as the suspension of damage during endurance testing. Experimental results are supported by the numerical descriptions of the behaviour of composites, which can be captured by a FEA conducted in a synthetic dynamic environment. In the end, the conditions that govern vibration fatigue failure were unravelled, incorporating both experimental and numerical investigations. Finally, this dissertation will conclude highlighting the most interesting points that emerged throughout this project while suggesting how they can be exploited to pave the way for interesting future works.

Date of Award	28 Nov 2019
Original language	English
Awarding Institution	University of Bristol
Supervisor	Luiz F Kawashita (Supervisor) & Dario Di Maio (Supervisor)