A coupled MD-FE simulation method accounting for interphases in nanoparticle filled thermoplastics.

A coupled MD-FE simulation method accounting for interphases in nanoparticle filled thermoplastics.

(Drittmittelfinanzierte Gruppenförderung – Teilprojekt)

Titel des Gesamtprojektes: SPP 1369: Polymer Solid Contacts: Interfaces and Interphases
Projektleitung:
Projektbeteiligte:
Projektstart: 1. Februar 2011
Projektende: 28. Februar 2014
Akronym:
Mittelgeber: DFG / Schwerpunktprogramm (SPP)
URL:

Abstract

This proposal aims at an extension of a recently developed, hybrid MD-FE simulation scheme towards its application to materials dominated by polymer-solid interphases. Only particle-based methods are able to intrinsically resolve microstructure and mechanical behavior of interphases. Therefore, we proceed with the following setup: A coarse-grained MD domain, which contains a single nanoparticle and as much polymer as necessary to ensure bulk behavior at the boundary, is included into a FE do-main. The FE boundary is used to apply various types of deformations and to record the overall stress responses of particle, surrounding interphase and bulk. With these data, the parameters of a purely continuous counterpart to the hybrid setup are iteratively adjusted until it behaves identically. As its main feature, the continuous ersatz-model substitutes the interphase between particle and polymer by an interface governed by a surface energy in the sense of Gibbs. This can be understood as a condensation of micro-scale property profiles within the 3-D interphase into a 2-D continuum mechanical model. Ultimately, after homogenizing the continuous ersatzmodel, macroscopic structure simulations allowing for a due consideration of interphase effects as occurring around nanoparticles are to be realized.

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