Abstract
The popularity of woven fabric composites (WFC) has increased recently in the aerospace industries due to their lightweight property, low thermal expansion and high flexibility. Several researches related to mechanical properties of these materials have been carried out, but those focused on fatigue characteristic of these materials are very limited in author’s knowledge. In this study, a simple original experimental device for pure bending fatigue tests is developed, and bending fatigue characteristic of WFC is investigated experimentally in detail using this device. Bending fatigue tests are conducted to acquire trends of S-N diagrams. Fatigue of WFC exhibits similar tendency as metals, and damage accumulation by bending fatigue is verified. Also, a stress distribution in the unit cell of tri-axially woven fabric composites (TWFC) under bending deformation is analyzed by finite element method (FEM) analysis to detect where a fatigue failure would initiate in TWFC for different levels of curvature. These results show that the maximum tensile and compressive stresses are located at the overlapping section of yarns. This means the possibility of bending fatigue failure is the highest at that area. Overall experimental results correspond to these analytical predictions.
