Statistical Analysis of the Fatigue Failure Phenomenon of Powder Bed by Loading with Dynamic Repeated Tensile Stress [Translated]†

Abstract

To study more quantitatively the fatigue failure phenomenon of powder beds, which was earlier discovered and reported by a part of the authors, this study was an attempt to obtain the relation between repeated tensile stress and fatigue life, which is usually represented by S-N relation, in a wide range of the repeating number N. Experiments were carried out by using vibration to exert dynamic repeated tensile load on the powder bed, with a vertically vibrating cell and a horizontally splitting cell. The frequency of vibration used was in the region of 5–300 Hz, and Kanto loam powder (JIS-11), fused alumina powder and lactose powder were used as samples. The results obtained are analyzed statistically and quantitatively concerning the distribution of fatigue failure life. It is found that within the limited range of the number of repeated stress less than 106, the existence of a lower limit of tensile stress (endurance limit) where the powder bed fails is confirmed at a stress ratio of the order of 0.7. The distribution of fatigue life is expressed by a Weibull distribution, and then it is shown quantitatively that the distribution of fatigue life of the powder bed is wide compared with other kinds of material, and it is suggested that the S-N relation of the powder bed obtained previously can be divided into two ranges, a sloping part and a horizontal part.† This report was originally printed in KAGAKU KOGAKU RONBUNSHU, 11(2), 186-192 (1985) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Chemical Engineers, Japan.