Humidity Effect on Mechanical Properties of Seashell by Molecular Dynamics Simulations and Nano-Indentation Experiments

Mollusks are known as the high performance bio-Nano composites with hierarchical irregular layers. They are combination of organic and inorganic materials. The aim of this paper is to determine the hardness and elastic modulus of the Top Neck mollusk shells with Nano-indentation process at the various humidity of 0%, 3%, 20%, 50% and 70%. However, the Nano-indentation test is an important empirical method to characterize mechanical properties like elastic modulus and hardness in Nano-scale; due to some limitations, it’s not applicable to investigate the effect of some physical parameters on the mechanical hardness i.e. humidity. Therefore, the molecular dynamics (MD) simulation is an alternative attractive method. Here, it is selected to simulate the mechanical properties of the Top Neck mollusk shells in various humidity conditions. The MD results show that the hardness of the bio-Nano composites obtained by the cubic indenter have a good consistency with the experimental data. This accuracy is shown for the elastic modulus obtained by the spherical indenter. It can be deduced that indenter type with the presence of water molecules results from significant sample weakening. Eventually, the elastic modulus and hardness decrease in the Nanocomposite Top Neck mollusk shells. Moreover, the indentation rate doesn’t influence on the elastic modulus and hardness of the samples.

کلیدواژه ها:

Layered Nano composite ، Seashell ، Nano indentation ، Molecular dynamics simulation ، Humidity