Weft direction pseudo-thermomechanical fatigue behaviors of T300/Polyimide-380 2.5D woven composites

This work elaborates the weft direction in-phase thermomechanical fatigue (IP TMF) behaviors of T300/PI-380 2.5D-WCs for the temperature variation between 100 and 300 degrees C for the first time. Results show that the IP TMF responses of 2.5D-WCs exhibit a low cycle fatigue characterization, which approximately linear decreases with the increase of cycle number. The hysteresis loops shifted to the right confirm an elongation of specimen during the IP TMF process. The residual stiffness and residual strength behaviors are also investigated in the case of TMF, and the corresponding numeric models are proposed based on the damage mechanics. Moreover, fracture morphologies of 2.5D-WCs under the IP TMF loading have been explored by means of SEM and X-rays obser-vations. Finally, a probable failure mechanism for the weft direction IP TMF behaviors of 2.5D-WCs is proposed. This work provides a new benchmark in studying high-temperature fatigue properties of resin matrix 2.5D woven composites.

Automated summary

This study elaborates the weft direction in-phase thermomechanical fatigue (IP TMF) behaviors of T300/PI-380 2.5D-WCs for the temperature variation between 100 and 300 degrees C for the first time. Results show that the IP TMF responses of 2.5D-WCs exhibit low cycle fatigue characteristics with decreasing trend in line with the increase of cycle number. The residual stiffness and residual strength behaviors are investigated and numerical models are proposed based on damage mechanics. Fracture morphologies of 2.5D-WCs under IP TMF loading have been explored. A probable failure mechanism for the weft direction IP TMF behaviors of 2.5D-WCs is proposed. This work provides a new benchmark in studying high-temperature fatigue properties of resin matrix 2.5D woven composites.