LIMITATIONS AND EXTENSIONS OF THE MAKISHIMA MACKENZIE MODEL

Abstract

The Makishima Mackenzie model, used to predict the elastic properties of glass, is explored in terms of both accuracy and predictive properties. Its limitations are outlined, in particular for borate glass, and a new framework is proposed to explain the mechanics that underlie the elasticity of network systems. This framework explains the limitations of the Makishima Mackenzie model, and why it functions in many but not all cases. The overall level of rigidity of the system can be predicted with the counts of the number of constraints and degrees of freedom in a system. Simulations are also performed that explore the dependency of elastic properties on various variables. The density of a system is found to be independent of elasticity, while the average coordination number is found to be strongly dependent. A new equation is determined that connects the Young’s modulus and the average coordi- nation number, applicable for constrained systems.