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Molecular dynamics study of phonon transport in graphyne nanotubes

Submitted by Ali Ramazani on

We determine the thermal conductivities of a, b, and g graphyne nanotubes (GNTs) as well as of carbon
nanotubes (CNTs) using molecular dynamics simulations and the Green-Kubo relationship over the
temperature range 50e400 K. We find that GNTs demonstrate considerably lower thermal conductivity
than CNTs with the same diameter and length. Among a (alpha), b (beta), and g (gama)-GNTs, g-GNT has the highest thermal
conductivity at all temperatures. By comparing the phonon transport properties of GNTs with CNTs, we

Theoretical studies on lattice-oriented growth of single-walled carbon nanotubes on sapphire

Submitted by Zhengwei Li on

In this work, a theoretical study is performed to quantitatively understand the van der Waals interactions between single-walled carbon nanotubes (SWNTs) and sapphire substrates. The energetically preferred alignment directions of SWNTs on A-, R- and M-planes and the random alignment on the C-plane predicted by this study are all in good agreement with experiments. It is also shown that smaller SWNTs have better alignment than larger SWNTs due to their stronger interaction with sapphire substrate.

Stress-Life Fatigue Testing Basics

Submitted by Deniz Yalcin on

ADMET CEO and Chief Engineer Richard Gedney's article on fatigue testing applications was published on the Quality Magazine August 2017 issue. 

The article starts with brief descriptions of the four stages of metal fatigue:

Stage 1: Crack Initiation

Stage 2: : Slip Band or Stage 1 Crack Growth

Stage 3: Stage II Crack Growth

Stage 4: Ductile Failure 

Abaqus Python : reading odb file for field frame data

Submitted by sidd04mech on

Hi,

I am running a python script to do some post processing on Abaqus odb file. While running it on Abaqus/Explicite output file I found it was taking more than usual time. And after timing the run I got the surprise that the most time consuming thing what just to read the time value for each frame. I have the script below.

def main():

odb=openOdb('F:/Scripting/.../.../Example.odb') 

stkeys=odb.steps.keys()

stp=odb.steps[stkeys[-1]]

frms=stp.frames

PhD Scholarship Available at USQ Australia

Submitted by Xuesen Zeng on

Research Topic – Manufacture of Aerospace Structures using Automated Fibre Placement.

Carbon Fibre Reinforced Plastic (CFRP) composites are being used increasingly in the load-bearing structure of aerospace vehicles. Automation is vital for better productivity of these large structures. This project will lead to the establishment of a state-of-the-art automated fibre placement (AFP) research capability at the Centre for Future Materials (CFM). This project will be key to ensuring the success and future growth of the aerospace sector in Queensland and Australia.

Ph.D. Student Positions in Computational Materials Science and Mechanics

Submitted by AnterEl-Azab on

Several Ph.D. student positions are available in phase field and mesoscale plasticity areas at Purdue University’s School of Materials Engineering. In addition to meeting all admission requirements, the ideal student would be one who is theory and computations oriented, with background in Fortran 90 and/or C++ skills and reasonable knowledge in mechanics and microstructure science of materials. Students with M.S. degree in mechanical engineering/mechanics, aerospace engineering/mechanics or in materials modeling and simulations are desirable for these position. To start in January 2018, a prospective domestic student needs to apply by the middle of October and an international student by October 1, 2017. For inquiry, please send email to Professor Anter El-Azab (aelazab [at] purdue.edu).

Journal Club for September 2017: Some recent developments in constitutive modeling of glassy polymers

Submitted by Alireza Amirkhizi on

The physics of glassy materials is a fascinating area of research. On one hand, the statistical mechanics understanding of their behavior is an active and exciting area of research. On the other hand, it is still quite challenging to develop and calibrate predictive constitutive models that reproduce all the observed behaviors. Many of the physical aspects the thermo-mechanics and ageing behavior of glasses are what actually make their constitutive modeling complex.

A Hybrid Multi-Scale Model of Crystal Plasticity for Handling Stress Concentrations

Submitted by Ali Ramazani on

Microstructural effects become important at regions of stress concentrators such as notches,
cracks and contact surfaces. A multiscale model is presented that efficiently captures microstructural
details at such critical regions. The approach is based on a multiresolution mesh that includes an
explicit microstructure representation at critical regions where stresses are localized. At regions farther
away from the stress concentration, a reduced order model that statistically captures the effect of the

Sandwich plates using Higher order theories

Submitted by Anonymous (not verified) on

Hi,

While modeling laminated composites we use their material properties (stiffness matrix) to compute the ABD matrix. When E_z of the core is much higher than E_x and E_y, how can we model such a plate using 2D FEM?