Blog posts

Faculty Position at Duke University

Submitted by John E. Dolbow on Thu, 11/02/2006 - 19:40

DEPARTMENT OF MECHANICAL ENGINEERING AND MATERIALS SCIENCE

PRATT SCHOOL OF ENGINEERING

The Department of Mechanical Engineering and Materials Science invites applications for tenure-track faculty positions. Two tenure-track appointments are anticipated and are open to all ranks, Assistant, Associate and Full Professor level. Applications are invited from candidates with research interests in autonomous vehicles and robotic systems, conventional and alternative energy technology, and MEMS/NEMS devices. Applications will also be accepted for allied mechanical engineering disciplines such as nonlinear dynamics and control, sensor technology, small and micro-scale propulsion systems, aerodynamics and aeroelasticity, thermal sciences, and vehicle dynamics.

Successful candidates are expected to establish a vibrant research program, obtain competitive external research funding, and participate actively in teaching at both the undergraduate and graduate levels. Applicants should submit a cover letter describing their research interests and qualifications, a curriculum vitae, and the names and addresses of three references. Please submit your application to mems-search [at] mems.duke.edu as a PDF (preferred) or Word file attached to your email. Duke University is an Affirmative Action/Equal Opportunity Employer.

How to post a video?

Submitted by Teng Li on Thu, 11/02/2006 - 19:10

video

iMechTube

Sometimes a video can be more convenient and effective than words on delivering a message. Now you can embed videos in your post in iMechanica. As a demonstration, I first embed a video below I made previously on how to make hyperlinks in your post. If you're interested in posting a video in iMechanica, read the following instructions:

How to embed a video in your post?
Step 1: Sign up a free account at YouTube.com, a website you can share videos online. Upon sign up, you can upload videos to YouTube. Follow the easy directions there. Of course you may want to read copyright tips of YouTube before uploading.
Step 2: Once uploaded, your video will have a Unique URL. You can always provide a hyperlink of the video in your post. To directly embed the video into a post, you need to use the html code automatically generated by YouTube, which you can easily find below the unique URL in the video information. Copy the entire html code.
Step 3: Since the current setting of the default text editor of iMechanica (those MS-word-type buttons above the textbox, called TinyMCE) does not support video yet, you need to turn it off and just use plain html. To turn off TinyMCE, click "my account" on the left sidebar, then click "edit" tab. Below "Account information" box, find "TinyMCE rich-text settings" and click it to expand the box. In the Default state, it shows "true" (means TinyMCE is on). Click the drop-down list and choose "false" . Scroll down to the bottom and click "Submit". Now TinyMCE is turned off.
Step 4: Start to post a new entry. Now you should see a Body textbox without any buttons. Paste the YouTube html code into the box. You can add any description above or below the code. If you want, you can also use any html editor to prepare your post and copy/paste the entire html file into the box.
Step 5: Preview your post then submit. Now all iMech users can view your video without leaving your post!
Of course, you can always turn TinyMCE back on by repeating Step 3.
We're still improving the video function in iMechanica. If you have any creative ideas to better achieve such a function, welcome to leave your comment below.
Enjoy vlogging in iMech.

Nanoscale incipient asperity sliding and interface micro-slip assessed by the measurement of tangential contact stiffness

Submitted by Yanfei Gao on Thu, 11/02/2006 - 13:13

Experiments with a multidimensional nano-contact system (Lucas, Hay, and Oliver, J. Mater. Res. 2004) have shown that, prior to kinetic frictional sliding, there is a significant reduction of the tangential contact stiffness relative to the elastic prediction. The reduction occurs at contact sizes below about 50~200nm for aluminum single crystals and several other materials. Using a cohesive interface model, we find that this reduction corresponds to a transition from a small-scale-slip to large-scale-slip condition of the interface.

The effect of long-range elastic interactions on the toroidal moment of polarization in a ferroelectric nanoparticle

Submitted by Jie Wang on Thu, 11/02/2006 - 07:23

research

long-range elastic interactions

toroidal moment of polarization

ferroelectric nanoparticle

The effect of long-range (LR) elastic interactions on the toroidal moment of polarization in a two-dimensional ferroelectric particle is investigated using a phase field model. The phase field simulations exhibit vortex patterns with purely toroidal moments of polarization and negligible macroscopic polarization when the spontaneous strains are low and the simulated ferroelectric size is small. However, a monodomain structure with a zero toroidal moment of polarization is formed when the spontaneous strains are high in small simulated ferroelectrics, indicating that, because of the LR elastic interactions, high values of spontaneous strains hinder the formation of polarization vortices in ferroelectric particles. Applied Physics Letters 88, 182904 (2006)

Computational Research in Heat and Mass Transfer - Position available at Sandia National Labs, Livermore, CA

Submitted by Jonathan Zimmerman on Wed, 11/01/2006 - 20:44

job

We are in need of computational scientists to carry out heat and mass transfer research. The research is focused on gaining basic understanding of physical processes through theory and numerical experiments. The scientist may work on several different projects and must be able to apply research results to impact engineering projects. We are interested in candidates with skills in the areas of forced and natural convection heat transfer, gas flow in multiphase systems, material and chemical processes, hydrogen technology, and renewable energy systems. We are seeking candidates who can employ an appropriate combination of analytical and computational methods in problem-solving.

Candidates should have working knowledge in one or more of the following topical areas: multiphase systems, electrochemical systems, material processes, and/or renewable energy systems. Experience with computational fluid dynamics is desired, both compressible and incompressible flows, as well as methods development and highperformance computing. Candidates should be able to synthesize information from
physical and numerical experiments to solve engineering problems. We work on a dynamic and ever-changing set of problems. Successful candidates will be flexible and demonstrate the ability to rapidly master new physical areas.

Computational Structural Mechanics R&D Position available at Sandia National Labs, Livermore, CA

Submitted by Jonathan Zimmerman on Wed, 11/01/2006 - 20:41

job

The Multi-Physics Modeling and Simulation Department at Sandia National Laboratories, California, is seeking a technical staff member to develop finite element-based simulation codes for linear and nonlinear solid mechanics and/or to perform solid mechanics and structural dynamics modeling and simulation. Typical departmental programs include: detailed analyses of weapon systems; design guidance of weapon components through analysis; development of forging and welding modeling capabilities; pressure vessel analysis including aging and failure; penetration modeling; ground shock and hydrodynamics modeling and simulations; failure model development and implementation (metals and composites); thermal and dynamic analysis of artillery projectiles; and electromagnetics and EM wave propagation analysis.

Postdoc position in the modeling and simulation of fracture available at Sandia National Labs, Livermore, CA

Submitted by Jonathan Zimmerman on Wed, 11/01/2006 - 20:37

job

The Mechanics of Materials Department performs fundamental experimental and analytical studies to understand the mechanical behavior of materials. Our experimental work covers the entire discovery-characterization-validation spectrum. Motivated by theory and observations, we develop models and the necessary numerical methods to simulate both deformation and failure under various mechanical and environmental loading conditions. The fidelity of our models and simulations varies from atomic to
continuum scales and is driven by both fundamental studies in material behavior and specific Sandia applications.

We are seeking a post-doctoral candidate with experience and interest in developing numerical methods and models for fracture to assist with a variety of material failure modeling and simulation activities. Knowledge of fracture mechanics and experience in numerical methods and code development are required. Also desired is experience with computational fracture methods, such as adaptive insertion, strain localization, and partition of unity methods for incorporating cohesive zone approaches to modeling fracture in a finite element framework. The position offers a unique opportunity to work closely with our team of fracture and
constitutive model developers, material scientists, experimentalists and analysts to investigate and model material failure in a variety of materials and systems from atomistic to continuum length scales.

Experimental Mechanics Position available at Sandia National Labs, Livermore, CA

Submitted by Jonathan Zimmerman on Wed, 11/01/2006 - 20:34

job

The Mechanics of Materials Department performs experimental and analytical studies to understand the mechanical behavior of materials. Our experimental work covers the entire discoverycharacterization-
validation spectrum. Motivated by observations, we develop models to simulate material responses under various loading and environmental conditions. The fidelity of our models and simulations vary from atomic to continuum scales corresponding to the requirement of Sandia applications. Accuracy of the models for specific applications is validated by experimental data. Numerical codes are developed to allow implementation of the
material models for high performance computing simulations.

The highly motivated scientist or engineer with expertise in experimental mechanics will work as a part of a diverse team in our state-of-the-art laboratories. The applicant is expected to develop and apply experimental research methods in one or more of several research areas, including: material model development, failure
model development, rate-dependent material effects and advanced experimental methods/diagnostic technique development.

Computational Modeling Position available at Sandia National Labs, Livermore, CA

Submitted by Jonathan Zimmerman on Wed, 11/01/2006 - 20:02

job

The Mechanics of Materials Department performs experimental and analytical studies to understand the mechanical behavior of materials. Our experimental work covers the entire discoverycharacterization-validation spectrum. Motivated by observations, we develop models to simulate material responses under various loading and environmental conditions. The fidelity of our models and simulations vary from atomic to continuum scales corresponding to the requirement of Sandia applications. Accuracy of the models for specific applications is validated by experimental data. Numerical codes are developed to allow implementation of the material models for high performance computing simulations.

An applied mechanics engineer with a background in computational constitutive modeling development is sought to participate in our general continuum and multiscale model development effort. The applicant is also expected to implement models into Sandia computer codes for high performance computing simulations. In addition, the candidate will collaborate with structural analysts to apply these advanced models to Sandia applications.