Analysis of the impedance spectra of short conductive fiber-reinforced composites

作者：Torrents JM^*; Mason TO; Peled A; Shah SP; Garboczi EJ

来源：Journal of Materials Science, 2001, 36(16): 4003-4012.

DOI：10.1023/A:1017986608910

The presence of small amounts of short conductive fibers in a composite of finite matrix conductivity results in the subdivision of the one matrix impedance arc into two separate low and high frequency arcs in the complex impedance plane. These features are attributable to a "frequency-switchable" interfacial impedance on the fiber surfaces, rendering them insulating at DC and low AC frequencies, but conducting at intermediate frequencies. A combination of physical simulations (single wires in tap water) and pixel-based computer modeling was employed to investigate the roles of fiber pull-out, debonding, and orientation on the impedance response of fiber-reinforced composites. The ratio of the low frequency arc size to the overall DC resistance (gamma -parameter) is sensitive to pull-out and/or debonding, especially when a fiber just barely makes contact with the matrix. The gamma -parameter is also quite sensitive to fiber orientation with respect to the direction of the applied field. Ramifications for the characterization of cement, ceramic, and polymer matrix composites are discussed.

• 出版日期2001-8
• 单位西北大学