作者：

作者单位：

刊名：HIGH-PERFORMANCE Composites

ISSN：1081-9223

出版年：2008-01-05

卷：16

期：5

起页：9

止页：11

分类号：TQ175

语种：英文

关键词：

内容简介

In my last column, I discussed uniaxial flexural strength testing of fiber-reinforced ceramics, that is, simple three- or four-point bending of a strip of material of rectangular cross section (see "Learn More," p. 11). As was noted, the strength of this test specimen is sensitive to machining defects at its edges. Also, in many applications of fiber-reinforced ceramics (and unreinforced ceramics), the stress state is not uniaxial, but rather biaxial. Based on these considerations, biaxial flexural tests have been developed, at least two of which have become commonly used ASTM and ISO standards. One of the two is ASTMG 1499, introduced in 2001 and currently the primary ASTM standard for biaxial testing. In the ASTM G 1499 test method, a thin circular disk (the standard also permits the use of a thin square plate) is supported on a ring and loaded by a ring of smaller diameter. For that reason, it is commonly referred to as a ring-on-ring test. The goal is to induce a biaxial failure stress away from the edges of the specimen that can be calculated using simple, small-deflection plate theory.