Molecular dynamics simulation for the quantitative prediction of experimental tensile strength of a polymer material

Abstract

This paper presents a quantitative method for predicting the experimental value of the tensile strength of a polymer material by using molecular dynamics (MD) simulation. Because the tensile strength obtained by MD simulation is almost always higher than the experimental value, a solution is suggested in the present study. Several simulations varying simulation volumes (i.e., number of molecules) and tensile loading speeds (i.e., strain rate) were implemented; the results confirmed that the tensile strength decreases with increasing simulation volume and decreasing strain rate. Firstly, strength as a function of the simulation volume was determined based on Weibull statistics and then the relationship was extrapolated to a much higher number of molecules, which was equivalent to a real specimen. Secondly, the relationship between the tensile strength and strain rate was determined and it was extrapolated to match the strain rate in actual experiments. Consequently, a predicted strength was close to the experimental result.

Keywords

• Molecular dynamics
• Tensile strength
• Experimental value
• Volume dependence