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Pull-in instability of multi-phase nanocrystalline silicon beams under distributed electrostatic force

Submitted by M. Shaat on
research
actuated beams; nano-structured materials; nanocrystalline silicon; pull-in voltage; modified couple stress theory

The effects of the material structure on the pull-in instability of nano-actuated beams made of nanocrystalline silicon (Nc-Si) and subjected to a distributed electrostatic force are investigated. Nc-Si is represented as a multi-phase material composed of nano-sized grains, nano voids, and an amorphous-like interface to consider the effects of the interface, grain size, porosity, and the inhomogeneities surface energies on the elastic properties of the composite material.

Modeling of mechanical resonators used for nanocrystalline materials characterization and disease diagnosis of HIVs

Submitted by M. Shaat on
research
Bio-mass sensor
material characterization
disease diagnosis
distributed-parameter model
Frequency Shift

The modeling and performance of mechanical resonators used for mass detection of bio-cells, nanocrystalline materials characterization, and disease diagnosis of human immune-viruses (HIVs) are investigated. To simulate the real behavior of these mechanical resonators, a novel distributed-parameter model based on Euler-Bernoulli beam theory is developed. This model is equipped with a micromechanical model and an atomic lattice model to capture the inhomogeneity nature of the material microstructure.

Effects of grain size and microstructure rigid rotations on the bending behavior of nanocrystalline material beams

Submitted by M. Shaat on
research
nanocrystalline materials
micro/nano beams
nanostructured materials
couple stress theory
grain size effect

Due to the intensive decrease in grain sizes of nanocrystalline materials (NcMs), a large volume fraction of atoms reside in the interface regions between crystals forming an atom-cloud phase with a distinct atomic structure. Moreover, the surface to volume ratio of the grain increases, thus its surface energy will significantly affect the mechanical properties of NcMs.

 

Iterative nonlocal elasticity for Kirchhoff plates

Submitted by M. Shaat on
research
nonlocal elasticity; iterative solution; Kirchhoff plates; micro/nano plates; micro/nano beams

Recently, the nonlocal elasticity theories have been used in studying the different behaviors of micro/nanostructures. However, there is a complicity in applying the natural boundary conditions in the context of the nonlocal differential elasticity models. Also, the nonlocal integral elasticity could provide a suitable remedy for this type of problems but with paying highly computational efforts.

 

Physical and Mathematical Representations of Couple Stress Effects on Micro/Nanosolids

Submitted by M. Shaat on
research
Couple–stress; modified couple–stress; consistent couple–stress; microcontinuum mechanics; linear elasticity.

In the present paper, for linear elastic materials, effects of couple stresses on micro/nanosolids are physically discussed and mathematically represented in the context of the classical, the modified and the consistent couple–stress theories. Then, an evaluation is provided showing the validity and the limit of applicability of each one of these theories. At first, the possible couple stress effects on mechanics of particles and on continuum mechanics are represented.

Inverse distance weighting as a FEM shape function

Submitted by Abiy Fantaye on
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Computational Mechanics Forum
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research

Hello there!

I was thinking to use inverse distance  interpolation technique as a finite element shape function. However, I am not sure about its performance for finite element method, inverse distance interpolation was originally developed for geographic information system.

can anyone help me please?

thanks in advance!

Linking Abaqus 6.14-1 with Microsoft Visual Studio 12.0 (2013) and Composer XE 2013 SP1 (Update 1)

Submitted by Hidroxid on
research
Abqus
Intel fortran compiler
Visual studio

I am tryring to link Abaqus 6.14-1 with Microsoft Visual Studio 12.0 (2013) and Composer XE 2013 SP1 (Update 1) (complier version 14) based on some instrcutions mentioned in following links:

http://www.researchgate.net/post/how_can_i_link_the_abaqus64-bit_and_fortran

http://imechanica.org/node/15894

A new paper on Hencky-logarithmic strain by Prof. Neff

Submitted by arash_yavari on
research

Dear Colleagues:

I thought the following recent paper by Prof. Neff may be of interest to some of you.

http://arxiv.org/abs/1505.02203

This paper discusses the natural appearance of the  Hencky-logarithmic strain tensor together with the Hencky strain energy, which can be motivated from some purely geometrical (kinematical) arguments based on the geodesic distance on the general linear group of all invertible tensors GL(n).

Fracture strength of micro- and nano-scale silicon components

Submitted by Frank W. DelRio on
research
silicon
fracture
strength

Silicon devices are ubiquitous in many micro- and nano-scale technological applications, most notably microelectronics and microelectromechanical systems (MEMS).  Despite their widespread usage, however, issues related to uncertain mechanical reliability remain a major factor inhibiting the further advancement of device commercialization.  In particular, reliability issues related to the fracture of MEMS components have become increasingly important given continued reductions in critical feature sizes coupled with recent escalations in both MEMS device actuation forces and harsh u

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