Luoyu Roy Xu's blog

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ASME Congress IMECE08 Topic on the Mechanical Behavior of Nanocomposite Materials

Image courtesy of Starwood HotelsYou are invited to present your research work on the mechanical behavior of nanocomposite materials (Oct. 31-Nov. 6, 2008 in Boston, MA). This topic will be focused on systematic mechanics experiments, modeling and simulations to solve new challenging mechanics problems such the effect of nanofiller agglomeration on the stiffness and strength reduction; interfacial stress transferring and interface strength evaluation at the nanoscale.  Deadline for abstract submission is March 3, 2008 (next Monday).


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Openings for New Ph.D. Students on Composite Materials and Failure Mechanics at Vanderbilt University, USA

New students may start from January 2008 if the graduate students have previous research experience in solid mechanics (e.g., nano/micro-mechanics, computational mechanics) or material engineering (MD simulation, mechanical behaviors). Students will have the opportunities to conduct balanced experimental and computational work on the durabilty and impact failure of marine composite materials; failure and material designs of nanocomposite materials; or rehabilitation of infrastructure materials using composites and other materials.  An MS degree is required.


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Power of iMechanica during job hunting

In July 2007, my friend of a consulting company contacted me for recruiting a computational mechanics engineer. I told him that all my graduate students found jobs, and there are not many mechanics students in our small department. So, I posted his ad at iMechanica. Only after one week, he asked me to withdraw this ad! Why?

 

Because many high-qualified applicants contacted him in one week and, he’d give the offer right away.  I believe this example is an index of active user groups of iMechanica.


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A pool filled with non-newtonian fluid

They filled a pool with a mix of cornstarch and water made on a concrete mixer truck. It becomes a non-newtonian fluid. When stress is applied to the liquid it exhibits properties of a solid. Video was recorded at Barcelona, Spain.


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Tensile strength and fracture toughness of nanocomposite materials

Are not as high as we expected although very stiff and strong nanotubes or nanofibers (Young’s modulus E~1000GPa) are added into soft polymer matrices like epoxy (E~4GPa).  In our early investigation on the  systematic mechanical property characterizations of nanocomposites (Xu et al., Journal of Composite Materials, 2004--among top 5 in 2005;and top 10 in 2006 of the Most-Frequently-Read Articles in Journal of Composite Materials.) have shown that there was a very small increase (sometimes even decrease) of critical ultimate tensile/bending strengths, and mode-I fracture toughnesses in spite of complete chemical treatments of the interfacial bonding area, and uniform dispersions of nanofibers (click to view a TEM image). Similar experimental results were often reported in recent years. Therefore, mechanics analysis is extremely valuable before we make these “expensive” nanocomposite materials. Our goal is to provide in-depth mechanics insight, and future directions for nanocomposite development. Till now, nanocomposite materials are promising as multi-functional materials, rather than structural materials. Here we mainly focus on two critical parameters for structural materials: tensile strength and fracture toughness. We notice that other mechanical parameters such as compressive strengths and Young’s moduli of nanocomposite materials have slight increase over their matrices.


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Faculty Position of Structures/ Mechanics/Materials at Vanderbilt University

Vanderbilt University, Department of Civil and Environmental Engineering is seeking candidates to fill a tenure-track faculty position commencing Fall 2007.  Appointment at the assistant professor level is anticipated but higher ranks will be considered for truly outstanding candidates.  The successful candidate will have research and teaching expertise in structures with a research focus in one or more of the following areas:  structural health monitoring, systems-scale failure analysis, dynamic control, computational mechanics and micromechanics, advanced materials (e.g., nanocomposites, smart materials), nano-biosystems or failure analysis.  Synergy with the risk and reliability focus of the department is essential.


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