A multiscale, finite deformation formulation for surface stress effects on the coupled thermomechanical behavior of nanomaterials

✍ Scribed by Geng Yun; Harold S. Park

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 618 KB
• Volume: 197
• Category: Article
• ISSN: 0045-7825
• DOI: 10.1016/j.cma.2008.02.001

✦ Synopsis

We present a multiscale, finite deformation formulation that accounts for surface stress effects on the coupled thermomechanical behavior and properties of nanomaterials. The foundation of the work lies in the development of a multiscale surface Helmholtz free energy, which is constructed through utilization of the surface Cauchy-Born hypothesis. By doing so, temperature-dependent surface stress measures as well as a novel form of the heat equation are obtained directly from the surface free energy. The development of temperature-dependent surface stresses distinguishes the present approach, as the method can be utilized to study the behavior of nanomaterials by capturing the size-dependent variations in the thermoelastic properties with decreasing nanostructure size. The coupled heat and momentum equations are solved in 1D using a fully implicit, monolithic scheme, and show the importance of capturing surface stress effects in accurately modeling the thermomechanical behavior of nanoscale materials.