Plane strain fracture toughness selected materials

Room-Temperature Yield Strength and Plane Strain Fracture Toughness Data for Selected Engineering Materials... 

The fracture process is investigated for two glassy polymers polymethyl methacrylate (PMMA) and polycarbonate (PC) which are generally thou t to show a brittle and a ductile response respectively and thus selected to illustrate the method. These materials consist of commercial sheets (from Goodfellow) of 10 mm thickness which ensures plane strain conditions for both materials. Caution about plane strain conditions concerns primarily PC which is prone to develop plasticity and a 10 mm thickness appears reasonable according to analysis of the influence of the thickness on its toughness found in [6, 7]. 

Charpy impact testing can also be used to determine critical strain energy release rates, G/, and to estimate the values of fracture toughness in states of plane strain and plane stress, and G c, respectively (49,89). Hence, experimental data can be obtained from standardized Charpy notched impact test (CNIS) as to their relevance for material selection and design. 

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