Molecular Simulation for Flexibility of a Single Clay Layer

Citations Over TimeTop 13% of 2001 papers

Abstract

Molecular dynamics (MD) simulations have been performed to study the flexibility of smectite clay minerals. We aim at the quantitative understanding of the mechanical behavior of a single clay layer in a completely exfoliated state. The repeating unit of a clay layer is taken to be ao = 0.52 nm and bo = 0.902 nm with formula of 2Na1/3 Al2[Si11/3Al1/3]O10(OH)2 which corresponds to that of beidellite. When the size of the basic cell (A = 9.3 nm, B = 2.6 nm, and C = 5 nm) (denoted by A-type cell) is reduced by 3−40% in the A-direction, the stationary structure of a clay layer is obtained as a curved sheet with a 2:1 smectite-type layer structure. In such a curved state, the layer experiences a stress of 0.5−0.7 GPa. The layer structure of a clay fractures when the size of the same basic cell is reduced by more than 40%. The bending constant is estimated for a curved layer by plotting the inverse of the average radius against stress. The similar calculations are performed by reducing the size of the basic cell (A = 3.1 nm, B = 10.7 nm, and C = 5 nm) (denoted by B-type cell) in the B-direction. The clay layer is found to be more flexible along the A-axis direction than along the B-axis direction. When the microscopic structure of a curved clay layer is examined, it is concluded that the main origin of flexibility lies in the change of Si−O−Si angles in the silicate tetrahedral sheets rather than in the change of bond lengths.

Related Papers

• → Smectite alteration and its influence on the barrier properties of smectite clay for a repository(2008)55 cited
• → Thermal analysis of selected illite and smectite clay minerals. Part II. Smectite clay minerals(2005)26 cited
• Changes in flexibility of elite female soccer players resulting from a flexibility program or combined flexibility and strength program: A pilot study(1999)
• → Flexibility and productivity in complex production processes(1995)1 cited
• → Prerequisites for stretching use in physical education of high school female students(2020)