Elastic constants and homogenized moduli of gypsum structure based on Density Functional Theory

Elastic constants and homogenized properties of gypsum structure were investigated by first-principles method.The gypsum (chemical formula of CaSO4•2H2O) is an evaporite mineral and a kind of hydration product of anhydrite (chemical formula: CaSO4).Elastic constants are calculated based on Density Functional Theory (DFT), which can also contribute to provide information for investigate the anisotropy and mechanical properties of gypsum polycrystals.In addition, based on elastic constants (13 independent constants) of the monoclinic crystal, elastic properties of gypsum polycrystals are obtained.The Young's modulus, shear modulus, bulk modulus and Poisson's ration are derived.Therefore, it is fairly meaningful to study the elastic constants to understand the physical, chemical and mechanical properties of gypsum structure.Elastic constants can be used as the measure criterion of the resistance of a crystal to an externally applied stress.The calculated parameters are in excellent agreement with reference by Huang et al..