The mechanical strength of a ceramic porous hollow fiber

Abstract

The mechanical strength of inorganic porous hollow fibers is a critical constraint that limits their wide scale application. Various methods, including 3-point bending, 4-point bending, and diametrical compression are used for the quantification of the mechanical strength. Here, we show that these methods cannot be used in an interchangeable manner. For large sets of alumina hollow fibers, the parameters describing the cumulative probability of failure functions depend on the type of measurement, i.e., 3 or 4-point, the span size, and the measurement geometry. This implies that reporting data on mechanical properties of inorganic hollow fibers requires that extensive information about the experimental details is provided, and that a direct quantitative comparison between datasets is unjustifiable.The mechanical strength of the alumina hollow fibers tends to follow a normal distribution, or log-normal distribution, instead of the often used Weibull distribution. Monte Carlo simulations demonstrate that, especially at small sample set sizes, it is difficult to accurately determine the shape of the probability distribution. However, detailed knowledge of the type and the shape of this distribution function is essential when mechanical strength values are to be used in further design.

Direct interfacial polymerization onto thin ceramic hollow fibers

“…The α-alumina fibers prepared by dry-wet spinning based on NIPS have pores in the range of 350 nm (not shown here, see [23]). The fibers were coated with an AKP-30 smoothing layer by vertical dipcoating to reduce the pore size to approximately 100 nm, and to eliminate the presence of macrovoids close to or reaching the surface.…”

Multi-length scale microstructural design of micro-tubular Solid Oxide Fuel Cells for optimised power density and mechanical robustness

“…6). This geometry In manufacturing process, the trade-off between mechanical robustness and mass transport is often the prime concern when tailoring the microstructure towards different operating conditions in micro-tubular SOFCs [61][62][63]. For power density-oriented design, in which the length of the microchannel cannot be sacrificed, an alternative solution could be the compactness of the microchannels.…”

The effect of the production method on the mechanical strength of an alumina porous hollow fiber

“…The full details of the mechanical strength measurements and subsequent calculations is described in detail elsewhere [12,21,22].…”

“…An important factor impeding the use of these fibers is their mechanical strength. The measured strength depends strongly on the measurement method and subsequent statistical analysis, as was recently demonstrated by our group [12]. The mechanical strength of porous ceramics often follows the Weibull model, which is based on a weakest-link hypothesis [13].…”