Fracture mechanics of methane clathrate hydrates

JJ Liu and K Xu and L Yang and YW Lin and T Li and XZ Gao and ZS Zhang and JY Wu, ACTA MECHANICA SINICA, 37, 1387-1394 (2021).

DOI: 10.1007/s10409-021-01105-y

Fundamental mechanics of gas hydrates is of importance to evaluating geomechanical and geotechnical properties of gas hydrate deposits, but it remains largely unexplored yet due to insufficient direct experimental techniques and high-quality of gas hydrate samples. Here, classic molecular dynamic (MD) simulations are used to study the fracture mechanics of three main methane clathrate hydrates of sI, sH and sH types. The results show that the mechanical properties of those three methane clathrate hydrates are intrinsically different and are degraded by the presence of nanocracks. They show brittle facture and different fracture toughness. In terms of energy release rate, they are ranked as sH> sI > sH. Moreover, the three methane clathrate hydrates with nanocracks can be explained by a modified Griffith criterion. Moreover, it is intriguingly identified tip amorphization during the crack propagation process of the three methane clathrate hydrates, and sH methane clathrate hydrate with specific nanocrack exhibits slower crack propagation than other two methane clathrate hydrates.

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