سنگ گچ تحت بارگیری کششی
Abstract
1- Introduction
2- Simulation methodology
3- Result and discussion
4- Conclusion
References
Abstract
The behavior of pristine single crystal gypsum under tensile loading at a molecular level has been probed in this study based on simulations. Uniaxial stress type tensile loading situations demonstrate anisotropy in response. For both uniaxial and triaxial loading situations, the non-bonded part of the energy governs the response. The response behavior of the tensile stress strain curves in uniaxial and triaxial conditions have been correlated with changes in the molecular structure along with interlayer and intralayer separation distances and layer slippages.
Introduction
Gypsum is a naturally available sulfate mineral, chemically known as hydrous calcium sulfate CaSO4 2H2O. It is present as natural reserves in various parts of the world [1] and also in other planets such as Mars (as confirmed at ground level by Mars Exploration Rover Opportunity) [2]. The stability of the mineral on Mars was demonstrated in a recent study [3]. Gypsum was also observed to precipitate in natural sea ice [4]. It is one of the softest minerals with a Moh’s hardness of 1.5–2.0. It can also exist in different forms based on the amount of the water retained between the layers of CaSO4 structure such as in bassanite ðCaSO4 H2OÞ and anhydrite (CaSO4). It has been reported that understanding the behavioral mechanisms of hydrous phases of these naturally available minerals along with their phase transition characteristics under different loading situations is important in the study of Earth mantle dynamics which might reveal mechanisms for generation of deep focus earthquakes [5].