Mechanical properties and failure probability of compact agglomerates

• Description of the softening and damaging effects of moisture
• Identification of the directly varying relationship between loading rate and dry strength
• Evaluation of the coupled influence of moisture content and loading rate on the granule strength
• Comparison of the mechanical properties of fresh and fatigue-affected granules
• Description of the breakage and fragmentation pattern using X-ray μ-CT images

Handling of compact agglomerate products such as granules which are typically inhomogeneous porous and mechanically (contact) history-dependent, is usually carried out with excessive costs and energy requirements to achieve merely a satisfactory process efficiency and product quality, owing to their statistically distributed probability of failure (by plastic yield or breakage). Although their failure probability may depend on several material properties and process conditions, qualitative and statistically reliable quantitative information about the influences of such factors other than size is hardly known.This communication presents a pragmatic analysis of model-based data evaluation of experimental force–displacement and breakage behavior of granules under quasi-static uniaxial compression, that commonly occurs during product processing and handling. The coupled influences of moisture content and loading rate on the distributed micro and macro mechanical properties of granules are described. A comparison of the mechanical properties of fresh and fatigue-affected granules is also reported. Furthermore, the macroscopic breakage and fragmentation pattern recorded using X-ray micro-computed tomography is also presented.

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