An Investigation of Material Parameters Influencing Creep and Fatigue Life in Filament Wound Laminates

摘要

The results of the environmental (wet vs dry) effects on the biaxial fatigue and creep (stress-rupture) performance of glass reinforced plastics having 20 and 26 percent resin contents is presented. Characterization of the materials in regard to resin content and density determination, ultrasonic flaw detection, and residual stress are included. Correlation of ultrasonic flaw scan patterns with sites of principal failure is made. Residual strain measurements on ring specimens using both 'peel' and 'cut coupon' techniques are shown to indicate residual tensile stress on the inside surface of the ring and residual compression on the outside. The results of wet and dry biaxial fatigue experiments at nominal cycle rates of 200 cph are presented and compared. The results indicate no significant difference in performance of either of the materials considered for the wet and dry test environments used. The results of biaxial stress rupture experiments in progress for as long as 14 months are presented. Stress rupture experiments to date show that excessive deformation and failure due to sustained stresses is of secondary importance when compared to the more severe fatigue effects. (Author)