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Piezoresistivity of Ag NWs-PDMS nanocomposite

Submitted by mortezaamjadi on

In this work, we developed a conductive silver nanowire (AgNW)-PDMS composite thin film for a flexible strain sensing application. The piezoresistivity of AgNWs-PDMS nanocomposite thin film was experimentally investigated and analyzed by a computational model. The strain sensor shows a strong piezoresistivity with an average gauge factor in the ranges of 1.6 to 14 and a high stretchability up to 70 %. We found excellent agreement between our experiment and simulation results.

Carbon Nanotubes-Ecoflex Nanocomposite for Strain Sensing With Ultra-High Stretchability

Submitted by mortezaamjadi on

We developed highly stretchable, flexible and very soft conductors based on the carbon nanotubes (CNTs)-silicone rubber (Ecoflex®) nanocomposite thin films. The resistance of the CNTs-Ecoflex nanocomposite thin film was recovered to its original value under cyclic loading/unloading for strains as large as 510%. Failure strain of the CNTs-Ecoflex nanocomposite was measured to be about ~ 1380% showing its ultra-high stretchability and robustness.

Flexible and Sensitive Foot Pad for Sole Distributed Force Detection

Submitted by mortezaamjadi on

In this work, we develop high flexible and compressible porous PDMS structures by using sugar cubes as templates. Force sensitive resistor (FSR) sensors were fabricated by the filtration of the CNT solution inside the porous structure of PDMS. We found that sufficient acid treatment can increase the adhesion between CNTs and PDMS. FSR sensors respond the applied pressure and compressive strains by high linearity (R2>0.97) and sensitivity (GFs>2) with a reliable manner.

Z-mat files in ABAQUS

Submitted by mithil on
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Hello,

I am trying to figure out how to incorporate Z-mat files in ABAQUS to simulate complex constitutuve models of polymers. While I have worked with UMAT subroutines before Z-mat is something new. Can somebody explain why Z-mat is necessary and are there any differences between conventional UMAT/VUMAT and Z-mat files?

Thanks.

-Mithil

Title: Effect of Hygrothermal Aging on the Mechanical Properties of Fluorinated and Nonfluorinated Clay-Epoxy Nanocomposites

Submitted by SalahHamim on

Polymers absorb moisture due to their hydrophilicity. Absorption of moisture changes the functional, mechanical and chemical properties of the polymer. Since polymer based materials are being increasingly used for structural applications, its only fitting to investigate how moisture absorption translates to mechanical property change. This experimental study investigated the effect of moisture absorption on the mechanical properties of epoxy polymers and their clay nanocomposites. Previous research studies reported that the high aspect ratio of clay slowed down the absorption rate.

Dispersion properties of vortex-type monatomic lattices

Submitted by Giorgio Carta on

The paper presents a systematic study of dispersive waves in an elastic chiral lattice. Chirality is introduced through gyroscopes embedded into the junctions of a doubly periodic lattice. Bloch-Floquet waves are assumed to satisfy the quasi-periodicity conditions on the elementary cell.

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

Submitted by M. Shaat on

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

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

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.