<p>The piezoresistive behavior of short carbon fiber reinforced polyethylene (SCF/PE) composites is often used for structural health monitoring through electrical resistance measurement. The monitored resistance of the SCF/PE composites will change correspondingly when loading is applied. However, the resistance change versus material loading is usually not monotonous, and this nonmonotonic piezoresistive behavior limited the accuracy of the monitoring results. In this paper, the piezoresistive behavior of SCF/PE composites was investigated through injection molded tensile specimens. Cyclic strain/ stress loading was applied, and the resistance change versus loading was measured and characterized quantitatively. The influence of tensile loading rate, loading amplitude and carbon fiber content on the piezoresistive behavior of SCF/PE composites were investigated. Experiments were carried to clarify the microcosmic mechanism of the resistance change behavior of the SCF/PE composites. There are two mechanisms that determine the resistance change: one is related to SCF orientation, and the other is related to SCF spacing. At the beginning of the loading, the increase of SCF orientation caused by material strain dominated the resistance change. Higher SCF orientation will help the establishment of conductive SCF network, and decrease the measured resistance. As the loading continued to increase, the increase of SCF spacing caused by material strain was dominant. Increased SCF spacing will lead to the destruction of conductive SCF network, and result in the increase of resistance.</p>

Investigation on the Piezoresistive Behavior of Short Carbon Fiber Reinforced Polyethylene Composites

Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2021/volume/85314

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