Fatigue Behavior of a Plain-Woven Glass Fabric Laminate under Tension/Torsion Biaxial Loading

Abstract

Fatigue strength and stress-strain response of a plain-woven glass fabric laminate subjected to pulsating tension/pulsating torsion biaxial loading were investigated. Biaxial loads were proportionally applied. S-N curves at different biaxial stress ratios were obtained. For the S-N diagram, the normalized fatigue strength defined by the ratio between the cyclic biaxial stress and the static strength, was used. All data roughly locate on a slightly wide band on the normalized S-N diagram, although the tendency that the slope of the S-N curve becomes low with an increase of the shear stress component is distinguishable. Modulus decays both in tension and shear with respect to loading cycles under biaxial loading are almost the same as those under uniaxial tension and pure torsion loadings, respectively. The direction of matrix cracks is dependent on the principal stress direction under biaxial loading although it does not coincide with the direction of the principal plane.