A technique for real-time detecting, locating, and quantifying damage in large polymer composite structures made of carbon fibers and carbon nanotube networks

Abstract

A significant safety concern preventing extensive use of composite materials for large polymer composite structures is the ability to detect, locate, and quantify damages that occur at one or several locations in large polymer composite structures. Real-time health monitoring of large polymer composite structures improves their performance, durability, and reliability while minimizing the life cycle cost. In this article, we present a new, practical, and real-time structural health monitoring technique for detecting, locating, and quantifying damages in large polymer composite structures made of carbon fibers and carbon nanotube networks. In this technique, electrically conductive epoxy resin was prepared by dispersing multiwalled carbon nanotubes into epoxy matrix. This modified epoxy matrix was then incorporated with long carbon fibers to make large composite plates. Two sets of grid points made from silver-epoxy paste were mounted on the surface of the large plates. The first set was used to apply the constant electric current, and the second set was utilized to measure the electric potential. The electric potentials across the second set of grid points on the undamaged plate were measured and used as a reference set. Two different damages were created by drilling holes and by applying impact loading on the large plates. It is found that the electric potential between the contact points surrounding the damage changes. The significant change in electric potential corresponds to the damage location in the plates. As such, drilled holes, impact damages, and barely visible impact damages are detected, located, and quantified.

Global overview on advances in structural health monitoring platforms

“…However, the use of devices that can notice changes in the materials electrical properties can be less interesting, if the material durability is considered, as for example, on materials exposed to corrosive environments. Therefore, this technology is more restrictive than the SHM platform developed by Naghashpour and Van Hoa [83]. Nonetheless, if used in a combined form in the same global monitoring system for all the building components, the probability of early damage occurrence detection in a large area of the material surface will be high.…”

“…The SHM platforms presented by Naghashpour and Van Hoa [83] and D'Alessandro et al [84] present some advantages relatively to the one developed by Nie et al [82], as, for example, a most distributed and lower intrusive sensing system. However, the use of devices that can notice changes in the materials electrical properties can be less interesting, if the material durability is considered, as for example, on materials exposed to corrosive environments.…”

“…A suitable method for local damage detection in large polymeric structures is presented by Naghashpour and Van Hoa [83]. In this work, an epoxy resin is modified by dispersion of multiwalled carbon nanotubes (95 % of purity, diameter between 2 and 20 nm, and length from 1 to 10 lm).…”

Analytical and numerical investigations on buckling behavior of nanotube structures

“…Many people have incorporated CNTs into polymer composites for detecting deformation and damage while enhancing physical properties of the structures [2][3][4][5]. Theoretical and experimental investigations on the use of CNTs in composite structures were carried out by many researchers, while analytical solutions are needed to be developed for CNT composite structures.…”

Nonlocal Theory to Analyse Nanotube Structures under Tension

“…Carbon nanotubes (CNTs) have been used as multifunctional materials while analytical and numerical analyses are required to be performed for CNT structures. Naghashpour and Hoa [1,2] dispersed CNTs into polymer composites to produce multifunctional polymer composites. Significant amount of experimental work on the use of CNTs in composites is being conducted while analytical and numerical analyses are required to be performed to obtain the properties and behaviors of nanocomposites.…”