The operation of many nano devices, such as nano electromechanical sensors and actuators, ultradense data storage using atomic force microscopes (AFM), nanostructured thermoelectric materials, molecular switches and nanowire LEDs, involves strong interaction between the mechanical and thermal energy domains. Computational modeling and analysis of thermomechanical interactions in nanomaterials and nanostructures is challenging because: (1) the mechanical description of the nanostructures must simultaneously account for the finite temperature effect and the finite size effect due to the presence of boundary and/or material interface where the continuum elastic constants are not well defined; (2) the description of phonon transport must account for a variety of phonon scattering mechanisms along with strain and nano effects (e.g. the dominance of ballistic phonon transport, phonon dispersion and density of states altering due to strain, boundary/interface transmission and reflection of phonons), which could make the physical model extremely complex; and (3) the length scales in nanostructured materials can vary across several orders of magnitude, ranging from a few nanometers of the nanoparticle size to millimeters of the size of the bulk structure. In this research, we develop computational models for coupled analysis of nano scale thermomechanical systems and explore utilizing the mechanical effects on the thermal transport in nanomaterials for various applications.

1. Y. Xu and G. Li, "Thermal Actuation using Nanocomposites: A Computational Analysis" Journal of Heat Transfer, accepted, 2012.
2. Y. Xu and G. Li, "Strain Effect Analysis on the Thermoelectric Figure of Merit in n-Type Si/Ge Nanocomposites" Journal of Applied Physics, vol. 111, 054318, 2012. (full text)
3. Y. Xu and G. Li, "Strain Effect Analysis on Phonon Thermal Conductivity of 2-D Nanocomposites," Journal of Applied Physics, vol. 106, art. no. 114302, 2009. (full text)
4. H. Zhao, Z. Tang, G. Li and N. R. Aluru, ``Quasiharmonic Models for the Calculation of Thermodynamic Properties of Crystalline Silicon under Strain'', Journal of Applied Physics, vol. 99, no. 6, art. no. 064314, 2006. (full text)