Fracture behavior of meso-fiber column in the stitched foam sandwich composites

The failure behavior of the single fiber column is complicated during the pull-out process in the stitched foam sandwich composites, so the carrying capacity of the structure can be unpredictable. The stitched foam sandwich composites were manufactured by the vacuum assisted resin injection (VARI) process. The interlaminar tension test (ITT) was employed to investigate the fracture process of the meso-specimen containing a single fiber column in the stitched foam sandwich composites. The effects of different fracture phenomena on the pulling friction process of the fiber column were discussed, and the fracture modes of the resin sufficient specimens were analyzed. The influences of the thread thickness on the key parameters such as force, displacement and energy absorption were studied. The influence of the resin deficiency caused by manufacture process on the performance of the stitched foam sandwich composite was analyzed. The results show that the energy absorption, key displacement parameters and maximum load of the stitched foam sandwich composite present an upward trend with the increase of the stitched thread thickness. However, the failure modes of the stitched foam sandwich composite also have a certain influence on the trend, which leads to the fluctuation of the trend. The energy absorption and maximum load of the resin deficient specimen are decreased due to the existence of defects.