Polymer fatigue: mechanism, mechanics and design

Abstract

Most structural failures are caused by fatigue such as aircraft wings, rotating blades, tires. During cyclic loading, polymers often accumulate substantial and irreversible damage, eventually leading to failure. To address this challenge, it is necessary to enhance the fatigue resistance of polymers. Herein, to provide a guiding theoretical basis and methodological framework for the research of high-durability polymers, this review presents polymer fatigue from the perspectives of mechanisms, mechanics and design, covering four types of polymers, including thermosets, thermoplastics, elastomers and hydrogels: i) fatigue tests, damage accumulation theories and fatigue crack growth models; ii) crack initiation and fatigue crack propagation of the four polymers; iii) factors affecting polymer fatigue properties, which influence fatigue resistance through both internal and external aspects; and iv) anti-fatigue mechanisms and strategies across multiple length scales. Finally, we discuss recent advances, challenges and future developments. New mechanism and mechanical theory have enhanced our understanding of the principles of fatigue resistance, while new designs have improved fatigue properties. It is hoped that this review will greatly promote the development of fatigue research and provide strong support for the design and application of next-generation anti-fatigue polymers.