Skip to main content

research

Feedback-Accelerated Picard Iteration for Orbit Propagation and Lambert’s Problem

Submitted by Xuechuan Wang on

This paper presents a new Feedback-Accelerated Picard Iteration method for solving long-term orbit propagation problems and perturbed Lambert’s problems. This method is developed by combining the collocation method and the variational iteration method over large-time-steps. The resulting iterative formulae are explicitly derived so that they can be directly adopted to solve problems in orbital mechanics. Several typical orbit regimes incorporating high-order gravity and air drag force are used to demonstrate the application of the proposed method in orbit propagation.

The 2nd International Conference on Advanced Modelling of Wave Propagation in Solids

Submitted by kolman on

The 2nd International Conference on Advanced Modelling of Wave Propagation in Solids

 

September 17-21 2018

 

Institute of Thermomechanics, The Czech Academy of Sciences, Prague, Czech Republic

 

The 2nd International Conference on Advanced Modelling of Wave Propagation in Solids intends to concentrate on topics such as:

Harnessing Surface Wrinkling-Cracking Patterns for Tunable Optical Transmittance

Submitted by Zhengwei Li on

Optical devices and systems with tunable optical transmittance have recently attracted great interest due to their wide range of applications. However, the reported methods of realizing tunable optical transmittance still suffer from complex fabrication processes, high cost, unstable materials or low tuning range. In this study, we report a simple, cheap, and highly effective approach to achieve large tuning range of optical transmittance through harnessing surface wrinkling-cracking patterns on PDMS films.

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

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

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.

Postdoc/PhD position in Computational (solid and structural) Mechanics in Tel Aviv University

Submitted by ryvkin on

Recently developed mathematical tools based on the discrete Fourier transform will enable modeling of fracture phenomenon in materials with periodic hierarchical microstructure.

The postdoc position is for one or two years, and PhD is a usual Phd program.  More info on the project is in attached file.

Gyro-elastic beams for the vibration reduction of long flexural systems

Submitted by Giorgio Carta on

The paper presents a model of a chiral multi-structure incorporating gyro-elastic beams. Floquet–Bloch waves in periodic chiral systems are investigated in detail, with the emphasis on localization and the formation of standing waves. It is found that gyricity leads to low-frequency standing modes and generation of stop-bands. A design of an earthquake protection system is offered here, as an interesting application of vibration isolation. Theoretical results are accompanied by numerical simulations in the time-harmonic regime.