Fatigue Behavior of IM7/BMI 5250-4 Composite at Room and Elevated Temperatures.

摘要

The tension-tension fatigue and tension-compression fatigue behaviors of the IM7/BMI 5250-4 composite were investigated. The tension-tension fatigue of the composite with 0/90 and plus or minus 45 fiber orientations was studied at 23, 170, and 190 deg C. The tension-compression fatigue of the composite with 0/90 fiber orientation was examined at 23 deg C. The tensile and compressive properties of the composite were also evaluated at room and elevated temperatures for both 0/90 and plus or minus 45 fiber orientations. Elevated temperature had little effect on the tensile properties of the 0/90 fiber orientation, but strongly influenced the plus or minus 45 tensile properties as well as the compressive properties of both fiber orientations. The 0/90 cross-ply exhibited a much stronger tension-tension fatigue performance than the plus or minus 45 cross-ply. Elevated temperature had little influence on the tension-tension fatigue response of both fiber orientations. The 0/90 composite exhibited reduced fatigue lives under tension-compression fatigue compared to the tension-tension cycling. The increased influence of the matrix on tension-compression fatigue response is evident.