Cutting Tests: A New Method to Determine the Fracture Toughness of Polymeric Materials

摘要

In modern materials science, how to accurately determine the fracture behaviour of engineering materials has been a longstanding problem [1-4]. Nowadays, the most widely used approach is linear elastic fracture mechanics (LEFM) analysis, which defines the fracture toughness in terms of the stress-intensity factor, K, or the strain-energy release rate, G [5]. Accordingly, standard measurement methods have been developed for polymers [6-8], which were initially applied to metals [9]. In practice, however, it remains a challenging task to determine the fracture toughness of tough polymers by using the existing standard methods, especially when there is an accompanying low yield stress. Such a combination leads to both crack growth and crack blunting which are difficult to separate. In addition it is impractical to apply the methods for polymeric thin films/paints or micro fabricated materials, owing to the stringent requirements for the shape and/or size of specimens.