Elastic Constant Prediction of Nacrite: Molecular Dynamics Simulations

A study of structural and mechanical properties of Nacrite using Molecular Dynamics Simulations based on energy minimization technique was investigated. Several mechanical properties have been calculated, such as the full elastic constants tensors, shear modulus, bulk modulus, Young modulus along a, b and c directions. The S- and P-wave velocities as well as Poisson ratio were also evaluated. The obtained elastic constant shows that C11≈C22 and higher than C33, indicating that Nacrite is more flexible in a and b direction than c one. The predicted bulk and shear modulus are respectively equal to 56.41 and 20.28 GPa. The Poisson’s ratios exhibit prominent anisotropy, with values ranging from 0.03 to 0.53. The Young’s modulus in the [100] and [010] directions (E1 and E2) is larger than E3 (Young moduli in[001] direction). In this study Vp=17.59 Km/s, Vs=8.68 Km/s and giving Vp/Vs ratio equal to 2.02. All these results reveal that Nacrite is less compressible than the other clays (kaolinite). All calculations were performed using GULP program.