Fatigue of hybrid glass/carbon composites: 3D computational studies

3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus compression cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension–tension cyclic loading, but might have negative effect on the lifetime under compression-compression, and has mixed effect for the tension–compression cyclic loading. Further, it was observed that while the fiber misalignment has some potential for increasing the fracture toughness of the hybrid composites, it speeds up the fiber damage and leads to the shortening of fatigue life.