Roughness and Angularity of Fragments from Meteorite Disruption Experiments

In this study, we set out to explore the relationship between fracture roughness and sample strength. We analyze 45 fragments of Aba Panu, Allende, and Tamdakht, three meteorites that have been strength-tested to disruption, to determine whether their shape or texture is correlated with measured compressive strength. A primary goal is to understand whether these exterior properties correlate with more challenging strength-related measurements. We first scan the samples and construct high-fidelity 3D models. The gradient-based angularity index AI g and the rms slope roughness metric theta rms are applied to all nine samples, and their validity and any correlation between them are analyzed. We find that different sample subsets show significant variation in both correlation strength and direction. We also find AI g to be of questionable validity in its application to highly angular samples. Based on our methodology and results, we do not find sufficient separation between the roughness values of samples to allow distinct identification of the three meteorites based on roughness alone. Additionally, neither metric shows a strong correlation with the strength of individual fragments. We do find, however, that the spread of the fragment strength distribution within a given meteorite has some correlation with its average roughness metric. Increased fragment roughness may imply greater structural heterogeneity and therefore potentially weaker behavior at larger sizes. We only have significant data sets for two meteorites, however, which are insufficient to correlate meteorite fracture roughness to meteorite strength in any simple way.