CAMP March Newsletter: Page 5
So far the team has developed an analytical model for a CNT composite using the nonlocal continuum theory approach. First and second order long wave approximations to the nonlocal theory solution are being studied. It is shown that the second order approximation yields more accurate results than the first order approximation (which is used by other researchers). The internal characteristic length (atomic length) for the nonlocal theory solution is derived through finite element analysis (FEA). Since it is not computationally efficient to model the entire CNT composite, a small piece which represents the material properties of the composite (called representative volume element or RVE) is modeled. See Figure 8. The RVE is modeled with very fine mesh so as to obtain a solution using classical elasticity. Alternatively, the internal characteristic length could be obtained from experiments. Once the unknown constant in nonlocal theory solution is obtained from FEM (or experiments) for an RVE, the computation for the composite is very efficient. Nonlocal theory is very appropriate for nano-scale structures wherein the interaction between atoms (especially adjacent atoms) has a big influence on the behavior of the structure. By using the nonlocal theory, stress is a function of strain in the entire domain which is similar to the behavior of atoms in nano-scale structures. Numerical example results using nonlocal, FEM, and classical elasticity for CNT composites are being studied. Unlike the classical elasticity results, the first moment obtained from stress distributions using the nonlocal theory is equal to the results obtained from the numerical FEM calculations. Wave propagation in elastic media is also studied using the second order approximation. Phonon dispersion results show that both first order and second order approximations give results close to the lattice dynamics dispersion. See Figure 9.
Distinguished University Professor /CAMP Director S.V. Babu Visits IMEC in Belgium
Distinguished University Professor S.V. Babu recently visited IMEC in Belgium. IMEC is a world-leading independent research center in nanoelectronics and nanotechnology. IMEC vzw is headquartered in Leuven, Belgium, has a sister company in the Netherlands, IMEC-NL, offices in the US, China and Taiwan, and representatives in Japan. The Center’s More Moore research aims at semiconductor scaling towards sub-32nm nodes. With its More than Moore research, IMEC looks into technologies for nomadic embedded systems, wireless autonomous transducer solutions, biomedical electronics, photovoltaics, organic electronics and GaN power electronics.
Otis Technology, Inc. joins CAMP as a New Corporate Member.
Dr. Sulapha Peethamparan recently joined CAMP. She is a new faculty member in Clarkson University’s Department of Civil and Environmental Engineering. She received her doctoral degree in Civil Engineering from Purdue University and worked as a postdoctoral researcher in the department of Civil and Environmental Engineering at Princeton University before joining Clarkson in 2008. Professor Peethamparan’s research interests include the following: the development of sustainable construction materials by using industrial by-products such as cement kiln dust, fly ash, slag and silica fume; the mechanism of Portland and oil well cement hydration; the setting kinetics of cements; micro-/nano-scale characterization of cement/cementitious materials; forensic analyses of deteriorated concrete; and lime/cementitious soil stabilization.