Experimental study on the bending properties and failure mechanism of 3D integrated woven spacer composites at room and cryogenic temperature

Three-point bending tests at room and liquid nitrogen temperature (as low as -196. °C) are conducted on the 3D integrated woven spacer composites with different core heights. Macrofracture morphology and SEM micrographs are examined to understand the deformation and failure mechanism. The results show that the bending properties at liquid nitrogen temperature are improved significantly than those at room temperature. Meanwhile, the bending properties both at room and liquid nitrogen temperature can be affected greatly by the core height. Moreover, the damage and failure patterns of composites vary with the core height and test temperature. At room temperature, three typical failure mechanism have been obtained for composites with different core heights. At liquid nitrogen temperature, the composites show gradual failure process which extends from the external layers of the compression face to the interior core layers. Furthermore, the brittle failure feature becomes more obvious and the interfacial adhesion capacity is enhanced significantly.