In situ speckle observation of Tyrano/BMAS composites in shear strength measurements

摘要

Strain profiles of specimens during interlaminar shear strength tests, short beam and double-notched compression, were measured by a speckle interference method using Tyrano~(TR)-related fiber-reinforced BaO-MgO-Al_2O_3-SiO_2 glass matrix composites with different surface finished fibers. The speckle interference method could detect changes in shear strain during the tests before the initiation of crack(s). Crack initiation could be detected earlier/easier by the speckle interference method than by video monitoring in both tests. Surface finish affected the shear strain profiles in the specimens. Sliding at the interface seemed to be detected in the composites reinforced with Tyrano fiber having a carbon layer. The speckle interference method is useful for measuring strains over wide areas of the specimens.