Selected topics in nanomechanics of engineering and biology systems
讲座名称：
Selected topics in nanomechanics of engineering and biology systems
讲座时间：
2009-12-27
讲座人：
高华健
形式：
校区：
兴庆校区
实践学分：
讲座内容：
Current research in my research group is focused on nanomechanics of engineering and biological systems. For biological systems, we use continuum mechanics, statistical mechanics and atomistic simulations to study how biological materials such as bone, gecko and cell achieve their mechanical robustness through structural hierarchy. The critical issues under investigation include stiffness, toughness, contact, adhesion, viscoelasticity, diffusion, size effects, convergent evolution, flaw tolerance, optimal shape, aspect ratios, self-assembly, endocytosis, etc. For engineering systems, we have been using molecular dynamics simulations and continuum modeling tools to study deformation, diffusion, growth, grain boundaries, stress evolution and failure in thin films and nanocrystalline materials.
In this talk, I will discuss our recent studies on the mechanics of focal adhesions in cell-substrate interactions as well as the mechanics of plastic deformation in nanocrystalline materials. The first topic has to do with efforts aimed to explain experiments that cells can strongly sense mechanical properties of their surroundings. We consider clusters of specific receptor-ligand bonds that link an animal cell to an extracellular matrix. To understand the mechanical responses of cell adhesions, we develop a stochastic-elasticity model of a periodic array of adhesion clusters between two elastic media subjected to inclined loads, in which stochastic descriptions of molecular bonds and elastic descriptions of interfacial traction are unified in a single modeling framework. The results show that elasticity can play a key role in cell-substrate adhesion by modulating the lifetime of focal adhesions across many orders of magnitude. The predictions of our model provide feasible explanations for a wide range of experimental observations. The second topic is concerned with attempts to explain recent experiments that plastic strains in nanocrystalline aluminum and gold films are partially recoverable.
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