Determination of out‐of‐plane electrical resistivity for nonoxide ceramic matrix composites

Abstract

The understanding of the directional dependence of electrical properties in composite materials is essential to develop an accurate electromechanical model for these materials. However, determining the out-of-plane electrical resistivity in composite materials is a challenging task due to the architectural complexity of these materials and the different electrical conductivity of the composite constituents. Moreover, the small thickness of most CMC panels imposes physical difficulties on measuring the out-of-plane electrical resistivity directly. This work provides an indirect method for determining the out-of-plane electrical resistivity for composite materials while introducing the concept of length constant. This method was utilized and successfully verified for three ceramic matrix composite systems with significantly different electrical properties. The proposed method can potentially be employed for other composite systems with conductive phases. K E Y W O R D S ceramic matrix composites (CMCs), electrical properties, non-destructive evaluation techniques, resistivity

The use of electric potential drop techniques to detect delamination in a melt‐infiltrated SiC‐based composite

“…DCPD is a method of electrical sensing that has been shown to be sensitive to the growth of transverse cracks in metals during fatigue crack growth experiments, 2–4 fiber and composite damage in C‐fiber reinforced polymer matrix composite systems 5–11 and transverse matrix cracking in ceramic matrix composite systems 11–20 . For all these studies, the emphasis is on in‐plane damage.…”

“…DCPD is a method of electrical sensing that has been shown to be sensitive to the growth of transverse cracks in metals during fatigue crack growth experiments, [2][3][4] fiber and composite damage in C-fiber reinforced polymer matrix composite systems [5][6][7][8][9][10][11] and transverse matrix cracking in ceramic matrix composite systems. [11][12][13][14][15][16][17][18][19][20] For all these studies, the emphasis is on in-plane damage. There has been some work on using DCPD to monitor interlaminar crack growth in CMCs at room 21 and elevated 22 temperature.…”