Multifunctional Shear Pressed CNT Sheets for Strain Sensing and Composite Joint Toughening.

摘要

This research program investigated critical fabrication aspects, mechanical and electrical properties, and potential applications of a novel carbon nanotube material, named shear-pressed sheet. This material is fabricated from the chemical vapor deposition grown, tall aligned carbon nanotube arrays, with the use of automated shear-pressing device. It was shown that such sheets, having typically 50-200 micron thickness, are self-sustained and sufficiently stiff to be removed from the substrate, handled without its shape distortion and then used either in a dry form or as a resin-infused prepreg for interleaving laminated composites and their bonded joints. Extensive set of double-cantilever beam tests of composite laminates with integrated shear-pressed sheets showed substantial, up to two times, improvement in the Mode I interlaminar fracture toughness. Experimental single-lap and double-lap joints of composites with integrated shear-pressed sheet interleaves were manufactured and experimentally evaluated. Embedded carbon nanotube shear-pressed sheets and drawn sheets showed excellent electrical resistance sensitivity and thus a potential for being used as in-situ strain monitoring devices which are practically non-intrusive and may simultaneously provide fracture toughness enhancement.