Fracture mechanics characterization of polymer composites for aerospace applications

Fracmre mechanics tests that quantify the delamination resistance of FRP composites determine the rate of change in strain energy per unit area of delamination (i.e. the 

Polymer Composites in the Aerospace Industry. http //dx.doi.oi l0.1016/B978-0-85709-523-7.00008-6 Copyright 2015 Elsevier Ltd. All rights reserved. 

Strain energy release rate, which is the driving force for delamination propagation and denoted by the symbol G) [1,4]. Assessment of the long-term performance of FRP composites for aerospace apphcations requires consideration of the effects on their delamination resistance of both service loads and environmental exposure. 

This chapter will first discuss fracture mechanics applications to polymer composites in aerospace, and then compile the different test methods by type of load. The industiy-specific fracture mechanics test procedures for FRP composites, such as the Airbus Industries Test Method (AITM) or Boeing Support Specification (BSS), are essentially based on test procedures developed by national or international standardization agencies. This will be followed by a section with literature data to highlight selected effects of processing and material layup and type. Further sections will discuss non-unidirectional reinforcement and testing under environmental conditions that are relevant to aerospace applications, and the chapter concludes with an outlook on materials and test development trends. 

Sources of information are the websites of the Intemalional Organization for Standardization (ISO), the American Society for Testing and Materials International (ASTM) and the Japanese Standards Association (JSA) that issues Japan Industrial Standards (JIS) documents. Data from scientific and technical journals and information from materials manufacturers and users available through the internet have also been used. An important source of information on composites testing and materials data are Refs [9—11], which was issued by ASTM, and its revision and extension, which is currentiy prepared by a nonprofit organization (i.e. the Composite Materials Handbook 17 version G) [12]. 

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Fracture mechanics characterization of polymer composites for aerospace applications... 

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