Abstract
The primary purpose of this paper is to study the influence of the surface roughness and interfacial pressure on the tangential AC breakdown strength (BDS) of solid-solid interfaces experimentally. Three-dimensional surface texture parameters are utilized to characterize the morphology of the polymer surfaces. Experiments were performed using samples made of crosslinked polyethylene (XLPE) at three different contact pressures. Surface roughness was varied by polishing the surfaces using four different sandpapers of different roughness. Each surface topography was then assessed using a 3 − D optical profilometer. Next, the samples were assembled under ambient laboratory conditions. Experimental results showed a good correlation between the tangential BDS and the surface roughness. The results suggested that reducing the surface roughness resulted in a decreased mean height of the surface asperities by nearly 97%. As a result, the tangential BDS rose by a factor of 1.85 − 2.15 with increasing pressure. Likewise, increased contact pressure yielded augmented tangential BDS values by a factor of 1.4 − 1.7 following the decrease of the roughness.
