APPLICABILITY OF MAGNETIC AND ELECTRIC EMISSION TECHNIQUES FOR DETECTING CRACK INITIATION IN IMPACT TESTS

摘要

The capability of the magnetic and electric emission effects to determine the onset of crack propagation in various materials is investigated. Magnetic signals can be observed only with ferromagnetic materials (i.e., steel). Brittle and ductile fracture onset can be determined as well. Almost all the materials under test exhibited electric signals. Their interpretation, however, differs with the material. In metals yield effects are described by electric signals but not fracture events. Plastic materials generally emit electric signals when breaking. Only one material of apolar molecule structure did not show any signal with the fracture event.