Fatigue behaviors of 2.5D woven composites at ambient and un-ambient temperatures

In-depth understanding of the fatigue behavior of woven composites at un-ambient temperatures is critical for their engineering applications, especially in aero-engine. Here, fatigue tests were conducted on 2.5D woven composites at an ambient temperature (AT) and an un-ambient temperature (U-AT) to investigate the fatigue characteristics and related damage mechanism. Results show that the fatigue life of this material at U-AT has a sudden increase phenomenon, alongside an abnormal behavior existing in residual strength. Additionally, the gradual right shift of the hysteresis loop was exhibited, which unambiguously reveals that during the cyclic loading, the samples were stretched alongside the increase in inclination of warp, causing the strengthening of mechanical properties in warp direction. The fatigue failure locations were mostly located on the intersection of warps and wefts, which is similar with the static fracture locations. Finally, based on the test data, fatigue life and residual stiffness models taking temperature into account were established.