scholarly journals Molecular dynamic simulation of the molecular characteristic and mechanical property of methane hydrate/ water/ ice mixture

2021 ◽  
Vol 261 ◽  
pp. 02004
Author(s):  
Jiawei Zhang ◽  
Bo Wang

The microscopic molecular characteristic will impact on the mechanical property of hydrate. Thus, molecular dynamics simulation is employed to investigate the molecular characteristic and mechanical property of methane hydrate/ water/ ice mixture system. The brittle fracture occurred during the tensile deformation of the system. Besides, the maximum stress of the hydrate/ water/ ice mixture system is lower than that of intact hydrate system. The fracture strain of studied system is smaller than that of pure hydrate system. The order parameters F3 and F4 can be used for determining the fracture position of mixture system and the changing of micro configuration on the mixture interface.

2020 ◽  
Vol 18 (1) ◽  
pp. 69-76
Author(s):  
Qiang Wang ◽  
Qizhong Tang ◽  
Sen Tian

AbstractMolecular dynamics (MD) analysis of methane hydrate is important for the application of methane hydrate technology. This study investigated the microstructure changes of sI methane hydrate and the laws of stress–strain evolution under the condition of compression and tension by using MD simulation. This study further explored the mechanical property and stability of sI methane hydrate under different stress states. Results showed that tensile and compressive failures produced an obvious size effect under a certain condition. At low temperature and high pressure, most of the clathrate hydrate maintained a stable structure in the tensile fracture process, during which only a small amount of unstable methane broke the structure, thereby, presenting a free-motion state. The methane hydrate cracked when the system reached the maximum stress in the loading process, in which the maximum compressive stress is larger than the tensile stress under the same experimental condition. This study provides a basis for understanding the microscopic stress characteristics of methane hydrate.


2011 ◽  
Vol 378-379 ◽  
pp. 7-10
Author(s):  
Gui Xue Bian ◽  
Yue Liang Chen ◽  
Jian Jun Hu ◽  
Li Xu

Molecular dynamics simulation was used to simulate the tension process of purity and containing impurity metal aluminum. Elastic constants of purity and containing impurity metal aluminum were calculated, and the effects of impurity on the elastic constants were also studied. The results show that O-Al bond and Al-Al bond near oxygen atoms could be the sites of crack nucleation or growth under tensile load, the method can be extended to research mechanical properties of other metals and alloys structures.


2018 ◽  
Vol 170 ◽  
pp. 09011
Author(s):  
D. Sudac ◽  
J. Obhođaš ◽  
K. Nađ ◽  
V. Valković

Relatively recently, in the last 20 years, it was discovered that methane hydrate (MH) deposits are globally distributed in the permafrost and oceans. Before 1965 when first deposits were discovered in nature, it was believed that MH can occur only in laboratory conditions or in vast parts of the Universe. Presently it is presumed that this solid crystalline compounds in which CH4 molecules occupies the water ice lattices (nominal chemical formula of MH is C4H62O23) can serve as an energy source favorably to the all of the world remaining conventional hydrocarbon sources. The worldwide estimates of MH deposits range from 2x1014 m3 to 3.053x1018 cubic meters. This uncertainty partly results from our limitations in geological understanding of the MH deposits, which is due to the relatively bad quality of data obtained by presently available seismic and electromagnetic techniques. Moreover, MH deposits can become vulnerable to climate changes, which were already occurring in geological past whit tremendous consequences for the global life on Earth. Thus, further development of advanced techniques is needed to enhance our abilities to better characterize, quantify and monitor the MH deposits. In the work presented 14 MeV neutrons and associated alpha particle imaging (API) where used to quantify the amount of MH in the sample. Samples were prepared from sea sediment, quartz sand and MH simulant. MH simulant with chemical formula C4H46O23 was made from sucrose (25 % by mass) and water. MH quantity was measured by measuring the carbon content in the sample [1-8].


2018 ◽  
Vol 92 (5) ◽  
pp. 840-846 ◽  
Author(s):  
Na Wei ◽  
Wan-Tong Sun ◽  
Ying-Feng Meng ◽  
An-Qi Liu ◽  
Shou-Wei Zhou ◽  
...  

2020 ◽  
Vol 5 (44) ◽  
pp. 13936-13950
Author(s):  
Weili Song ◽  
Xiaoliang Sun ◽  
Guanggang Zhou ◽  
Wenqi Huang ◽  
Guiwu Lu ◽  
...  

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