Overview

Current research areas include:

  • The characterization of nanoparticle reinforced polymers
  • Phase transformation response of shape memory alloys
  • Aging in polymeric based systems
  • Investigation of microstructure effects on properties of microporous materials for bioengineering

The research encompasses analytical, numerical and experimental investigation. Analytical micromechanics methods, finite element simulations of scanned material microstructures, and results from molecular level simulations are combined with continuum mechanics techniques to provide microstructurally based prediction of macroscopic environmental-mechanical response. On the experimental side, smaller scale testing includes optical and electron microscopy of samples with in situ loading, for example examining reorientation of martensitic variants with applied load in shape memory alloys. Macroscopic scale testing of samples in environmentally controlled chambers are also performed and the results of experiments are used to refine and better define models for advanced materials.

Research

Nanomine

The Material Genome Initiative launched in 2011 created a new era for top-down material design and discovery that aims at faster material deployment from research to commercialization. Using polymer nanocomposites as an exemplary case, this project focuses on developing the infrastructure and methodology in representation, evaluation, and prediction of optimal polymer nanocomposite material properties. This synergy combines material structure characterization, processing-structure correlation, physics-based finite element modeling, and a living data resource for polymer nanocomposite material data. Our research targets at the quantitative statistical correlation among the p-s-p domains and examines the underlying principles behind the influences such as interphase and surface chemistry.

Polymer Nonocomposites

Nanocomposites are polymers that have been reinforced with small quantities of nano-sized inclusions, defined as particles that have at least one characteristic dimension in the range of 1 to 100 nm. By introducing nano-sized particles, polymer nanocomposites radically differ from conventional polymer composites, and the natural structure and interactions of polymer molecule chains are disturbed on the interface between matrix and fillers, leading to fundamental changes in material properties in this interphase region. Our research thus aims to investigate and understand the mechanism and properties of polymer nanocomposite interphase using computational and experimental approaches in order to design and develop new polymer nanocomposite material systems.

Shapel Memory Alloys

Under the appropriate stress and thermal conditions, Shape Memory Alloys (SMAs) exhibit the ability to fully recover large deformations via "superelasticity" or "pseudoelasticity". The main objective of this work is to observe size effects and granular constraints in the elastic and transformation regimes of NiTi based SMAs. Experimental results (using diffraction and imaging techniques) reveal the strain and transformation maps of SMAs, which are compared with similar maps obtained from predictive models.