On the durability and lifetime prediction of filament wound composites

Abstract

This thesis investigates the durability and aging behavior of glass fiber/vinylester filament wound composites (FWCs) coupons obtained from real-life structures under various environmental conditions. Divided into four parts, the study looks into different material response towards different aging environments, appearance, failure cause and mechanisms and offers insights into its long-term performance and non-destructive characterization of such structures. Part 1 of the thesis concentrates on evaluating the impact of aging in both water and thermal environments. The thesis uses rigorous experimentation and analysis to investigate how exposure to these conditions affects the mechanical, physicochemical, and appearance properties of the material over time. Part 2 of the research focuses on cyclic aging environments. The aim of this section is to understand the impact of repeated cycles of common environmental factors, such as temperature fluctuations, irradiation, and humidity variations, on the material’s degradation behavior. The research aims to elucidate the cumulative effect of cyclic aging on the material. Part 3 of the thesis is dedicated to service life prediction of glass fiber/vinylester FWC as a function of material degradation response. The prediction model works by drawing upon the data gathered from Parts 1 and 2. Arrhenius rate degradation and its modified forms was used to estimate the material’s remaining useful life under static and cyclic aging regime. These models offer valuable insights for assessing the long-term durability and reliability of the material in practical applications. Finally, Part 4 introduces non-destructive micro-CT analysis as a tool for evaluating FWC. Through high-resolution imaging techniques, this section provides a detailed examination of the material’s microstructure, offering valuable information for understanding aging mechanisms and possible failure modes under loading. This thesis provides a comprehensive investigation of FWC, which can offer valuable insights for designing more durable parts and broaden the application areas for such structures.