Application of the essential work of fracture (EWF) concept for polymers, related blends and composites: A review

The essential work of fracture (EWF) concept has become very popular to characterize the plane stress toughness of ductile polymers and related systems. The widespread use of the EWF is due to the simple specimens' preparation, easy testing and simple data reduction procedure. Though the EWF method is usually used for mode-I type loading, it has been successfully adopted for mode-II and mode-III type deformations, too. Moreover, attempts have also been made to deduce plane strain toughness values from EWF tests. This paper critically reviews the application of the EWF to polymers, polymer blends and composites. The literature survey covers all major aspects of testing and related data reduction methods, and lists the EWF results achieved on different polymer systems. The latter are classified according to their synthesis/production and modifications. Special attention was paid to disclose the correlations between EWF and other fracture mechanics parameters, and to trace the EWF response to molecular and morphological parameters of the tested polymers.