MedeA® Application Notes for Aerospace

The effect of resin molecular architecture on the small strain elastic constants of diamine-cured epoxy thermosets has been studied using classical all-atom simulations conducted within the MedeA simulation environment. Batches of thermoset systems have been created using chemically similar di, tri and tetrafunctional resins, followed by calculation of stiffness and compliance matrices for each individual model. Analysis of the batches of topologically and geometrically distinct structures using the Hill-Walpole approach yields upper and lower bounds estimates of the moduli differing by typically 1%, enabling critical comparison with experimentally-measured values.

Effect of Resin Molecular Architecture on Epoxy Thermoset Mechanical Properties

Interfaces are present in most materials and have a large impact on mechanical properties such as stiffness and yield strength. Given that the properties of an interface can radically change by the presence of even minute amounts of impurities, it is of great interest to predict the effect of segregated atoms at interfaces.

As systematic experimental information on the impact of specific defect types on the grain boundary strength is hard to obtain, computational modelling is of great help.

Strength of Ni Grain Boundary and the Effect of Boron

Accurate measurements of diffusion coefficients of atoms in solids are difficult and deviations between different experiments can be several orders of magnitude. For the benchmark case of hydrogen diffusion in nickel first-principles calculations give a remarkable agreement with available experimental data especially near room temperature. Thus, computations of diffusion coefficients can be comparable in reliability with measured data. Simulations are possible for situations such as high strain, or slow processes where measurements are difficult or impractical.

Diffusion of Hydrogen in Nickel