Behavior of acoustic emission caused by microfracture in polycrystalline graphites

✍ Scribed by I. Ioka; S. Yoda; T. Konishi

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 729 KB
• Volume: 28
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(90)90336-w

✦ Synopsis

Acoustic emission (AE) was measured on four kinds of isotropic graphites under tensile and compressive loading. Observed AE events can be divided into two types, with low and high relative energy. The events with low relative energy were initially observed under a low stress level, continued to the fracture of the specimen. On the other hand, the events with high relative energy were observed from an even higher stress level. AE events with low and high relative energy corresponded to cleavage between basal planes within the filler grains and to microcracking in the binder region. respectively. The stress at which an AE event with high relative energy was first detected. the AE onset stress, was closely dependent upon the fracture stress of the graphite. Empirical equations related to the AE onset stress and the fracture strength under tensile and compressive loading were proposed to help in estimation of tensile and compressive strengths of a polycrystal~ine graphite using an AE technique.