Self-sensing via piezoresistivity of multiwall carbon nanotube-epoxy resin composite was studied in order to assess its feasibility in strain and damage detection. Self-sensing is an economical and durable component of Structural Health Monitoring of manufactured composite, in which the material is employed as sensor. Objective of the study centered on strain and damage sensing and particularly focused on how applied tension and /or inflicted damage affected electrical conductivity. The MWCNT-epoxy composite was manufactured with non-treated multiwall carbon-nanotubes. They were dispersed in the epoxy employing ultrasonic dispersion and mechanical mixing, prior to addition of curing agent. The samples were rectangular specimen of dimensions 150 mm × 25 mm × 5 mm. Surface electrodes were created with sliver paint, to which copper wire leads were wrapped and affixed with more silver paint or carbon based electrically conductive glue. Kelvin in-line resistivity measurement technique was adopted to assess and monitor composite resistivity. The technique minimizes contact resistance between electrodes and the composite, which could be order of magnitude larger than the material resistance. For strain sensing, the specimen was subjected to increasing tensile strain until failure. In damage sensing, the specimens received different depth surface cuts across their width. During the tensile strain testing the specimens failed at a typical strain of about 4%. The corresponding change in resistance was in range of 2–3%. In damage sensing mode, changes of up to 40% in resistance were recorded for 75% thickness deep damage. For lower depth damages, the change in resistivity were about 4%–10%. The data obtained so far indicate that with proper technique, self-sensing of CNT-epoxy resin composites could be a viable method for monitoring applied strain and structural integrity.

This content is only available via PDF.
You do not currently have access to this content.