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Hamid Souri's picture

Electrical properties and piezoresistive evaluation of polyurethane-based composites with carbon nano-materials

The present study assesses the applicability of carbon materials-embedded polyurethane (PU) composites characterized by high piezoresistive capability, as a traffic loading sensor. PU composites incorporating multi-wall carbon nanotubes (MWNTs), expanded graphite (EG), and a hybrid of MWNTs and graphite nanoplatelets (GNPs) were fabricated and their electrical conductivities were measured in an effort to determine the most suitable filler type for the piezoresistive sensor and its optimum content ratio.

Hamid Souri's picture

A facile method for transparent carbon nanosheets heater based on polyimide

In this work, a novel film heater in nanometer-scale thickness based on catalyst-free and transfer-free carbon nanosheets (CNSs) with properties similar to graphene is fabricated. Here, poly(amic acid) (PAA), which is composed of several aromatic hydrocarbon rings, is used as the carbon precursor of CNS films. Altering the polymer concentration easily controls the morphological, optical, and electrical properties of the CNS films obtained by carbonization of PAA thin films.

Search engine for postdoc or faculty posiotn in USA

What is best way to seach for postdoctoral position or faculty position in USA?

I am aware that in iMechanica some positions are posted but the number of positions is limitted. I would appriciate any advice from people in the US. Thanks!


Harley T. Johnson's picture

A critical thickness condition for graphene and other 2D materials

B. C. McGuigan, P. Pochet, and H. T. Johnson, Critical thickness for interface misfit dislocation formation in two-dimensional materials, Phys. Rev. B 93, 214103, 2016.


draw the mass gain curve over time


I want to draw the mass gain curve over time, it follows the Fick law but the results I obtained are either instantaneous or ramp.

how to draw?

thank you

Square to parallelogram

I am trying to model a rigid box which deforms into a parallelogram on application of

displacement/velocity. I have made a box using 4 rigid plates ,but when I apply

the shear force the plates lose contact. I have used no seperation technique 

it didn't help .kindly give a solution asap.

Fillet Weld in ABAQUS

Choose a channel featured in the header of iMechanica: 

Hello everyone,

I want to model a connection between two steel plates which form a T-section. The welds are fillet weld. Do you have any recommendation how to model the weld? One way I think of is to connect the two plates with two solid elements weld through tie constraint. You think that's a right way of doing that? 

soheil.tahmasbi's picture

Excessive rotation of Nodes/ ABAQUS explicit

Choose a channel featured in the header of iMechanica: 

I am simulating dynamic impact using B31 element type and general contact in ABAQUS Explicit and the job is aborted showing the error of "Excessive rotation of nodes". I, also, used mass scaling to control the run time.
Does anyone know how to control this problem?

I really appreciate your replies.


Alejandro Ortiz-Bernardin's picture

Linear smoothed polygonal and polyhedral finite elements

Paper Accepted for Publication in International Journal for Numerical Methods in Engineering

Linear smoothed polygonal and polyhedral finite elements

A. Francis, A. Ortiz-BernardinSPA. BordasS. Natarajan


Payam Soltani's picture

A short note on equal peak design for the pendulum tuned mass dampers

By: A. Deraemaeker and Payam Soltani
Pendulum tuned mass dampers (PTMDs) are used to passively mitigate the vibrations of tall structures and buildings. The main objective of this short note is to introduce analytical formulae for the optimum design of the linear PTMD coupled to an undamped primary system. Den Hartog's equal peak method is applied to derive the optimum design. With the mass ratio between the primary system and the PTMD, the optimum length and optimum damping of the pendulum are calculated. The formulae are presented in both dimensional and non-dimensional forms and are simple to apply in real applications. It is also shown that the vibration mitigation performance of the proposed optimum design precisely matches the results obtained by numerical optimisation techniques.
doi: 10.1177/1464419316652558

Dennis M. Kochmann's picture

Travel Grants for USACM Workshop on Nanoscale Computational Mechanics

A USACM Thematic Workshop on Recent Advances in Computational Methods for Nanoscale Phenomena will be held at the University of Michigan in Ann Arbor from August 29-31, 2016. The workshop website contains further information at

Harold S. Park's picture

Journal Club Theme of June 2016: 2D Materials: Current and Future Directions

Two-Dimensional (2D) materials have been widely studied since the discovery of graphene in 2004.  Many of the initial works on the various 2D materials (graphene, MoS2 and other transition metal dichalcogenides, black phosphorus, and others like the monochalcogenides) by mechanicians focused on issues like ideal strength, and appropriate methods to calculate the bending modulus.  Some of these, and other issues, were reviewed by Sulin Zhang in a J-Club from March 2015 (http://imechanica

D.Rittel's picture

phd position H2020 Marie Slodowska Curie ITN/ETN program

We are offering a PhD position to start this coming september at technion, Haifa, Israel, as advertised in the attached file.

To qualify, the candidates should hold an M.Sc. with thesis in mechanical/materials engineering and have passed the GRE with a grade of 85% or more.

The research will be experimental and numerical in character.

Postdoctoral Fellow at UCSF Medical Center

The Cardiac Biomechanics Laboratory at the University of California San Francisco Medical Center (UCSF) Division of Cardiothoracic Surgery and San Francisco VA Medical Center is seeking a hard working, motivated post-doctoral fellow to participate in biomedical engineering research involving the ascending thoracic aortic aneurysms (aTAA).  The post-doctoral fellow should be motivated to be on a career track to become an academic professor.  Our lab is NIH funded to investigate the biomechanics of aortic aneurysms and currently has 2 postdoctoral fellows, and are seeking a 3rd.  The goals ar

Arash_Yavari's picture

Nonlinear Elasticity in a Deforming Ambient Space

In this paper we formulate a nonlinear elasticity theory in which the ambient space is evolving. For a continuum moving in an evolving ambient space, we model time dependency of the metric by a time-dependent embedding of the ambient space in a larger manifold with a fixed background metric. We derive both the tangential and the normal governing equations. We then reduce the standard energy balance written in the larger ambient space to that in the evolving ambient space.

Seeking for a postdoc position

Dear Professors,

I am Xilei BIAN, from Shanghai University. I will complete my Ph. D degree this year, and I wish to apply a postdoctoral position related to nanostructured materials or advanced materials. 

I am familiar with and skilled in: Synchrotron Source and the data process, in-situ TEM/SEM, FIB, Instrumented nanoindentation, mechanical testing machine, XRD, DSC, etc.

Giorgio Carta's picture

Transmission and localisation in ordered and randomly-perturbed structured flexural systems

The paper presents a novel analysis of localisation and transmission properties of randomly-perturbed flexural systems. Attention is given to the study of propagation regimes and the connection with localised resonance modes in the context of Anderson's localisation. The analytical study is complemented with numerical simulations relevant to the design of efficient vibration isolation systems.


Eigenvalues, reflected and transmitted energy, localisation factors for the examined bi-coupled random system:

Mario Juha's picture

LES and RANS simulation of wind- and wave-forced oceanic turbulent boundary layers in shallow water with wall modeling

Large-eddy simulation (LES) and Reynolds-averaged Navier-Stokes (RANS) simulation of wind and wave forced oceanic turbulence in unstratified shallow water are performed in order to investigate the influence of wall modeling on results. The LES is also used to investigate the dependence of results on downwind and crosswind lengths of the computational domain, representative of a shallow shelf coastal ocean (10-to-30 m deep) unaffected by lateral boundaries.

Electroelasticity of polymer networks

This work introduces a new microscopically-motivated model for the electromechanical response of elastomers:

The merit of this novel model is demonstrated in the following paper

Mirkhalaf's picture

Polymer constitutive modelling: Formulation and computational aspects

  • This work formulates an elasto-viscoplastic model at finite strains.
  • A particularly efficient numerical integration algorithm is presented.
  • A closed-form analytical expression is derived for the consistent tangent operator.
  • The non-linear behaviour of polymers is captured in the numerical examples.
  • Quadratic rate of convergence is successfully achieved.
Douglas P Holmes's picture

Geometry and mechanics of thin growing bilayers

Matteo Pezzulla, Gabriel P. Smith, Paola Nardinocchi, and Douglas P. Holmes, Soft Matter, 12, 4435-4442, (2016).



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