Ohmic heating and mechanical stability of carbon fabric/green epoxy composites after incorporation of fly ash particles

Abstract

The objective of present research was to study the Ohmic heating and mechanical stability of carbon fabric/green epoxy laminated composites after incorporation of 0.5, 1 and 3 wt % unmilled and milled fly ash particles. The Ohmic heating behavior was analyzed by estimating temperature response rapidity, maximum temperature, and electric power efficiency from time-temperature curves of the composites when constant voltage of 5 V was applied for the duration of 120 s. The composites filled with 0.5 wt % milled fly ash showed rapid heating, high temperature generation and less power consumption. Later, the effect of 15, 30 and 60 min Ohmic heating action on structural and mechanical stability of 0.5 wt % fly ash filled composites was examined from DSC, SEM, tensile testing, dynamic mechanical analysis and creep testing. The composites filled with milled fly ash showed superior mechanical and viscoelastic stability than unmilled fly ash composites. This indicated faster heat transportation characteristics by milled fly ash particles to avoid local matrix melting around carbon fibres during Ohmic heating. The marginal loss in mechanical properties was found due to increased agglomeration tendency of fly ash particles under Ohmic heating.