Design criteria for particle attrition

Attrition and comminution are major effects that occur in handling and conveying systems of particulate solids. However, appropriate design tools based on reliable and significant bulk solids' properties are not available. In this paper we outline some preliminary steps and ideas to obtain such tools (by similarity to the design of solid machine parts). Furthermore, we show that particulate systems are damaged by constant as well as cyclic loads. In this sense most existing experimental systems could be analyzed and compared. The results gained by a new fatigue machine show clearly the effect of fatigue in compression up to 25000 cycles of loading. By introducing systems in which the strength properties of either single particles or particulate systems could be defined, their behavior is characterized. Moreover, two examples are analyzed: a rotary drum and a pneumatic conveying pipe line (in very dilute states). Both systems are actually affected by the same phenomenon (fatigue) at various ranges of loads.