Molecular Simulation Study on the Microscopic Structure and Mechanical Property of Defect-Containing sI Methane Hydrate

Abstract

The study of changes in the related mechanical property and microscopic structure of methane hydrate during the decomposition process are of vital significance to its exploitation and comprehensive utilization. This paper had employed the molecular dynamics (MD) method to investigate the influence of defects on the microscopic structure and mechanical property of the sI methane hydrate system, and to discover the mechanical property for the defect-containing hydrate system to maintain its brittle materials. Moreover, the stress-strain curve of each system was analyzed, and it was discovered that the presence of certain defects in the methane hydrate could promote its mechanical property; however, the system mechanical property would be reduced when the defects had reached a certain degree (particle deletion rate of 9.02% in this study). Besides, the microscopic structures of the sI methane hydrate before and after failure were analyzed using the F3 order parameter value method, and it was found that the F3 order parameters near the crack would be subject to great fluctuations at the time of failure of the hydrate structure. The phenomenon and conclusions drawn in this study provide a basis for the study of the microscopic structure and mechanical characteristics of methane hydrate.

Strengthening and weakening of methane hydrate by water vacancies

“…As is known, the structural I methane hydrate is the most common clathrate hydrate identified in nature, thereby it is taken into an investigation in this study (Cai et al, 2019). For construction of the molecular model of sI methane hydrate, the positions of water oxygen atoms are attained from Xray diffraction experimental data by McMullan et al (1965) Hydrogen atoms are initially covalently-bonded to the oxygen atoms in random directions, while the positions of hydrogen atoms are further determined based on the Bernal-Fowler rule, ensuring that the total dipole moment of water molecules is small.…”

Molecular Simulations of Adsorption and Energy Storage of R1234yf, R1234ze(z), R134a, R32, and their Mixtures in M-MOF-74 (M = Mg, Ni) Nanoparticles

“…MOFs have nanoscale pore structure, so it is difficult to examine the adsorption property of refrigerant in MOFs through conventional experiment and theoretical method. With the rapid development of computer technology, molecular simulation technique has been extensively applied in scientific research [16][17][18][19][20][21][22][23] . Plenty of literature suggests that, molecular simulation has become the third research means apart from experiment and theory 12,[24][25][26][27][28][29] .…”

Molecular Dynamics Simulation of the Cu/Au Nanoparticle Alloying Process

“…Simulation Model. In this paper, the large-scale atomic/molecular massively parallel simulator (LAMMPS [19]) was utilized for MD simulation, and the embedded atom method (EAM) potential [20][21][22] was utilized for describing atom interactions within the systems. The EAM potential energy between atoms was expressed as follows.…”