The Maximum Stress in Optical Glass Fibers Under Two-Point Bending

The maximum stress in optical glass fibers subjected to two-point bending was evaluated by E. Suhir, “Effect of the Nonlinear Behavior of the Material on Two-Point Bending of Optical Glass Fibers,” ASME Journal of Electronic Packaging, Vol. 114, pp. 246–250, taking into account the shift in the neutral axis due to the nonlinear stress-strain relationship of the materials. However, the resulting distribution of bending stress on the fiber cross-section is not realistic because it produces a nonzero axial force. In the present study, we derive the correct formulas for evaluating the maximum stress under the valid condition that the bending stress does not contribute to the axial force. Moreover, we employ the nonlinear stress-strain relationship containing a third-order term of strain, which is more appropriate for the materials than that utilized by Suhir.