Effect of loading path on fatigue degradation and stress-strain response of glass fabric composites under tension/torsion biaxial cyclic loading

摘要

The present paper shows the effect of loading path on the fatigue degradation of plain woven glass fabric polymer matrix composites under tension/torsion biaxial loadings. The loading path significantly affected the fatigue characteristics at lowcyclic fatigue. The effect of loading path on the fatigue strength and the modulus decay in shear with respect to the number of loading cycles was most significant when the normal stress was applied longer for each loading period. For such cases, thefatigue life became short and the shear modulus decreased much during an early stage of fatigue. The loading path also affected the internal damage accumulation. The matrix cracks were curved when the stresses were not applied proportionally. Peculiarphenomena were also observed in normal stress - normal strain curves both in tension and shear. A model was proposed to explain the phenomena. On the contrary, the effect of loading path on the fatigue characteristics was not distinguishable at highcyclic fatigue.