The significance of impact data for brittle non-metallic materials

Abstract

Experimental data for the impact energy of a number of brittle materials are reviewed and their significance discussed in terms of material properties and test conditions. For each material and test method several interpretations need to be considered but it is not always possible to extract meaningful information from the data. At one extreme, for strong, very brittle materials like ceramics, the impact strength may be controlled by the elastic energy in the specimen at the instant of fracture initiation. At the other extreme, for weaker or tougher materials like graphite and fibre reinforced plastics, the impact strength may be controlled by the work of fracture of the specimen. However, in many cases, the situation is less clear and it is emphasized that great care should be taken in the interpretation of test data.