Fractograph-fatigue crack growth kinetics relationship for a fiber reinforced composite

• Published in: Journal of materials science 2006-09, Vol.41 (17), p.5788-5792
• Main Authors: GAN, Yong X, AGLAN, Heshmat A
• Format: Article
• Language: English
• Subjects: Applied sciences; Composites; Crack propagation; Exact sciences and technology; Fatigue failure; Fiber composites; Forms of application and semi-finished materials; Fracture mechanics; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-006-0121-9

Fractography is widely used in post-failure analysis to identify fracture origin locations, stress characteristics and service environment. The fracture surface of filled polymer materials often provides clues to the initiation sites of crack, the growth mechanisms and the role of the reinforcement. The technique of scanning electron microscopy (SEM) is the most widely used method of studying fracture surface morphology. In addition, other techniques such as optical microscopy, transmission electron microscopy (TEM) and acoustic microscopy can provide useful complementary information. The SEM has been increasingly used for quantitative fractography in determination of mechanism of material failure. For polymeric and filled polymeric materials, the SEM serve as the key tool for evaluation of fracture surface features and the determination of failure mechanisms under either monotonic or cyclic tensile loading condition. The advantages of SEM include good depth of field and focus, and simple specimen preparation. The depth of focus is very important because both filled and unfilled polymeric materials display well-drawn and undulating nature of polymer chains under both overloading and cyclic loading conditions. This means that conventionally used optical microscopes are unable to capture the fracture surface features clearly because they are only in focus over a very limited small part of the cracking region. With SEM, it is possible to combine signals to create high resolution micrographs and yield different types of information (topographical, chemical, etc.).