Session: 12-16-01: Multiscale Models and Experimental Techniques for Composite Materials and Structures Count

Paper Number: 120080

120080 - Mesomechanics of Highly Filled Particle Reinforced Composites Using a Bonded Particle Method 

The mechanical behaviour of highly filled polymer composites is complex, exhibiting traits of both polymeric and granular materials with additional inelastic mechanisms introduced by interactions between the constituents.  How these mechanisms interact for a given mechanical loading scenario is dependent on material constituent properties, filler volume fraction, and aspects of the mechanical loading (strain rate, ambient temperature, confinement, and sample history). From a practical standpoint, validated constitutive models are needed to predict the homogenized behaviour of highly filled particle composites in complex thermal and mechanical loading scenarios. However, development, parameterization, and validation of such constitutive models for engineering applications is impeded both by the complexity in describing the underlying and interacting inelastic mechanisms and frequently by a paucity of experimental discovery and characterization data for materials.

Fortunately, highly filled polymer composites do share many features across different material systems. The polymer binder phase is typically operating either well above or well below its glass transition, and the binder and particles phases can delaminate at the mesoscale. We seek to take advantage of these known underlying behaviours at the mesoscale to better understand the characteristic behaviours of highly filled polymer composites.

We present a multi-scale study that explores mechanical behaviour under a variety of different loading states and material design space parameters on representative volumes (RV) of highly filled particle composites.  We use a minimalist bonded particle model (BPM) which represents solids as a collection of point particles connected by pairwise bonds. Different material properties such as stiffness, plasticity, and failure are captured by adjusting the functional form of bond forces. Our mesoscale modelling links material design parameters to emergent inelastic deformation mechanisms that drive the macroscale mechanical behaviour up to and including localization (deformation cracking that spans the representative volumes). We explore a variety of material design parameters, such as particulate to binder volume ratio, binder glass transition temperature, and binder-particulate interfacial failure and extract homogenized RV responses and microstructure evolution metrics. In particular, we note that the relation between the analysis of crack evolution of the RVs and bulk constitutive behaviour remains an open area of research. We summarize insights gained from these studies and their implications for macroscale constitutive modelling are discussed, including yield surface shapes, pressure dependence, damage evolution mechanisms and material failure criteria.

 

This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under contract DENA0003525. This abstract describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the abstract do not necessarily represent the views of the US Department of Energy or the United States Government.

 

Presenting Author: Kevin Long Sandia National Laboratories

Presenting Author Biography: Kevin Long is a staff member at Sandia National Laboratories focussed on the thermal-mechanics of polymers, polymer composites, foams, and composite laminates with an emphasis on micromechanics, finite-element analysis, and constitutive modeling.

Authors:

Joel Clemmer Sandia National Laboratories
Kevin Long Sandia National Laboratories
Judith Brown Sandia National Laboratories