Abstract
Doubly-convex cylindrical tablets compacted uniaxially from different particle-size fractions of “Di-Pac-Sugar” powder, have been fractured under diametral loading conditions employing the standard diametral compression test. The ratio of cylinder length to diameter (W/D) ranged from 0.476–1.06; the ratio of cylinder diameter to radius of curvature of the tablet faces (D/R) was varied from 0.0–1.184. An equation based on geometrical volume equivalence conditions, of a doubly-convex cylinder to that of a plane-faced cylinder, relating the tensile strength of the “material” to the fracture load and dimensions of doubly-convex cylindrical specimens, has been developed. This equation is valid for any compacted cylindrical tablet. Using this equation, it was possible to assess the tensile strength of doubly-convex tablets, and a shape factor has been defined. Also, the predicted fracture loads obtained by this equation are found to compare well with those values determined by utilizing a “stress factor” based on the photoelastic stress analysis. For higher ratios of W/D and smaller diameter values, the variation in the results calculated is found to be less than 5%. Meanwhile, for higher values of W/D, the geometrical end effect is reduced and the tensile fracture stress tends to become similar to that of a plane-faced specimen.
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Es-Saheb, M.H.H. Tensile fracture characteristics of double convex-faced cylindrical powder compacts. JOURNAL OF MATERIALS SCIENCE 31, 214–223 (1996). https://doi.org/10.1007/BF00355148
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DOI: https://doi.org/10.1007/BF00355148