Experimental study of high electric current effects in carbon/epoxy composites

Electrical and thermal behavior of the carbon fiber-reinforced epoxy composites subjected to relatively high (up to 75 A) steady electric currents is studied. A fully automated experimental setup for real time measurements of the electric current, resistance, voltage, and temperature in carbon fiber-reinforced epoxy matrix composites has been developed. A series of electrical characterization tests on IM7/977-3 unidirectional and symmetric cross-ply composite laminates have been performed and the effects of electric current magnitude and duration, electrical resistance, and associated thermal effects have been investigated. It is determined that electrical resistance exhibits time-dependent behavior. It is also found that application of an electric current leads to a significant temperature rise in the composites that is a result of the intense Joule heat produced in the electrically conductive carbon fibers as well as in the composite-electrode contact.

► Electrical and thermal behavior of electrified IM7/977-3 composites are studied.
► Relatively high (up to 75 A) steady electric currents are applied to the composites.
► Electric current, resistance, voltage, and temperature are measured in real time.
► Electrical resistance exhibits time-dependent behavior.
► Joule heating is significant and depends on the composite lay-up.