Load transfer from fiber to polymer matrix, studied by measuring the apparent elastic modulus of carbon fiber embedded in epoxy

Abstract

Load transfer from a single carbon ber to the surrounding epoxy matrix was studied by measuring the apparent tensile modulus of the ber while the ber was embedded in epoxy and comparing the apparent modulus (1650 GPa) with the real modulus (230 GPa). Thus, it was found that 87% of the tensile load applied to the ber was transferred to the epoxy.

Self-sensing and interfacial evaluation of Ni nanowire/polymer composites using electro-micromechanical technique

“…Apparent modulus and electrical resistance of two cases were not different significantly from each other, but rather higher in the aligned case. Apparent modulus is defined as the modulus of single carbon fiber embedded with polymer matrix under loading/unloading test, which can provide valuable information on interfacial adhesion between sensing fiber and embedded matrix as well as embedded matrix modulus [10]. The stress transferring effect due to the enhanced alignment could contribute to higher apparent modulus even at such a low volume percentage to some extent.…”

“…Electro-micromechanical technique has been studied as a feasible economical nondestructive evaluation (NDE) method for damage sensing, the characterization of interfacial properties because conductive nanocomposites can act as an inherent sensor in itself as well as a reinforcing fiber [10][11][12]. According to Park et al [13], carbon fiber damage inside nonconductive epoxy matrix composites could not be detected after the first fracture of sensor carbon fiber occurred, whereas the fiber fracture as well as matrix deformation could be detected consequently in electrical conductive matrix dispersed with carbon nanofiber by the change in electrical resistance.…”

Self-sensing and dispersive evaluation of single carbon fiber/carbon nanotube (CNT)-epoxy composites using electro-micromechanical technique and nondestructive acoustic emission

“…This tendency might be related to composites' apparent modulus, which can provide indirect information on interfacial adhesion. ''Apparent modulus" means the modulus of the embedded fiber in the matrix obtained from the stress-strain curve compared with the modulus of the carbon fiber itself [23][24][25]. The tensile deformation of a carbon fiber with a good degree of CNT dispersion might be less due to a higher composite modulus, whereas in a poor degree of CNT dispersion the weak interface might be accompanied by a lower composites modulus.…”

Dispersive evaluation and self-sensing of single-fiber/acid-treated CNT-epoxy nanocomposites using electromicromechanical techniques and acoustic emission

“…Films made of SWCNTs also possess a low sheet resistance and exhibit an optical transmittance in the visible spectrum comparable to that of commercial indium tin oxide (ITO), which is brittle ceramic. The electro-micromechanical technique [5][6][7] has been studied as an economical nondestructive evaluation (NDE) method for damage sensing, the characterization of interfacial properties, and nondestructive behavior because conductive fiber can act as sensor in itself as well as a reinforcing fiber [8,9]. Fiber damage in electrical insulator matrix can not be detected after the first fiber fracture occurred, whereas in electrical conductive matrix fiber fracture as well as matrix deformation can be detected continuously by electrical resistance measurement.…”