Accurate determination of system compliance and young's modulus for single fibers

Single fiber testing was conducted utilizing the ASTM D3379-89e1 standard to measure the Young's modulus for optical glass fibers. Upon analyzing the experimental data, it was discovered that procedural methods to account for system compliance resulted in a source of uncertainty due to the 12.6 % fiber diameter variability between different fibers tested. As a result, the 86.8 GPa Young's modulus determined included a significant 43.9 % uncertainty. A new method of data analysis was devised to take into account this fiber diameter variability, which lowered the uncertainty to 7.5 % and provided a Young's modulus of 61.4 GPa. Comparisons were made with the more recent ASTM C1557-03 standard that gave a similar 61.3 GPa Young's modulus. A large bias error of 41.6 % exists between the Young's modulus values determined by the two standard methods. The various analytical methods are discussed along with their estimates of uncertainty, the impact on micro-mechanics, and how to lower this uncertainty further. Copyright © 2011 by ASTM International.