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

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.

PhD Position (4 years) in Experimental Study of Nano-Composites

PhD Position (4 years) in Experimental Study of Nano-Composites

Center for Design, Manufactirung, and Materials, Skoltech, invites applications for a PhD position in Experimental Study of Nano Composites, starting in November 2017.

Zhengwei Li's picture

Harnessing Surface Wrinkling-Cracking Patterns for Tunable Optical Transmittance

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.

Konstantin Volokh's picture

On cavitation in rubberlike materials

Microscopic voids can irreversibly grow into the macroscopic ones under hydrostatic tension. To explain this phenomenon it was suggested in the literature to use the asymptotic value of the hydrostatic tension in the plateau yield-like region on the stress-stretch curve obtained for the neo-Hookean model. Such an explanation has two limitations: (a) it relies on analysis of only one material model and (b) the hyperelasticity theory is used for the explanation of the failure phenomenon.

Xuanhe Zhao's picture

NEW.Mech 2017 at MIT on October 14

New Mech

We would like to let you know that free registration for the upcoming 8th annual New England Workshop on the Mechanics of Materials and Structures (NEW.Mech 2017) is open now.  The NEW.Mech 2017 is taking place at MIT on October 14, 2017.

Stephan Rudykh's picture

[Deadline: Sept. 30] 16th European Mechanics of Materials Conference (EMMC-16) Nantes, France, March 26-28, 2018

Dear Colleagues, 16th European Mechanics of Materials Conference (EMMC-16) will be held in Nantes, France,  March 26th-28th, 2018. As part of this meeting, we are organizing a session (S9) to bring together experts in modelling, simulation, manufacturing and experimental investigation in the field of Functional and architectured materials to present and discuss recent advances.

pragtic's picture

WCFA workshop on Design and Fatigue of Weldments

This is the second announcement about the upcoming Workshop on Computational Fatigue Analysis 2017, this year dedicated to Design and Fatigue of Weldments (WCFA2017-DFW - http://www.pragtic.com/DFW.php). The workshop is held in Prague, Czech Republic in November 13-16, 2017. The key lecturer, who guides the audience through various issues of the fatigue analysis in welds, is Dr Zuheir Barsoum from KTH - Royal Institute of Technology in Sweden.

Ali Ramazani's picture

Molecular dynamics study of phonon transport in graphyne nanotubes

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

Zhengwei Li's picture

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

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.

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

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.

Konstantin Volokh's picture

Understanding the strength of bioinspired soft composites

Remarkable mechanical properties of biocomposites (bone, teeth, shell, antler etc.) are usually attributed to their special design where staggered mineral platelets are embedded in a protein matrix. Because of the high aspect ratio of the platelet the soft protein deforms in the shear mode predominantly providing the linkage for the hard inclusions. Mimicking Nature one might design materials with a similar architecture. 

DEADLINE: September 15th, 2017 | AMD/ASME Awards - Call for nominations 2017

 REMINDER: The deadline for nominations for the AMD/ASME awards is September 15th, 2017.

Information and details on each of the awards are provided below.

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Two positions at the Mechanical Engineering Department at the University of British Columbia

Two positions are open for Ph.D. or Masters students in the Department of Mechanical Engineering at the University of British Columbia, Vancouver, Canada. The positions are joined with the Modeling and Simulation group and the Micro and Nano mechanics laboratory. We are looking for skilled and highly motivated individuals to pursue a Ph.D. or M.A.Sc. in the area of multiscale modeling of materials and solids mechanics. Two projects are available:

Giorgio Carta's picture

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

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.

Mike Ciavarella's picture

1 phd position for NON-italian citizens at Politecnico di BARI - ITALY. Expires 12 sept

1 phd position for phd is reserved to non-italian citizens at Politecnico department of Mechanical engineering.

Attached the SELECTION CALL FOR ADMISSION TO THE RESEARCH DOCTORATE (Ph.D.) PROGRAMS – XXXIII CYCLE AT THE POLITECNICO DI BARI ACADEMIC YEAR 2017/2018 

Various options for research themes are available, also including solid mechanics, fatigue or contact mechanics.

See attachment or write for details at mciava AT poliba.it

Application expires on Sept.12 !!

PhD position at Boise State University

The Micron School of Materials Science and Engineering at Boise State University is seeking a PhD student to work on projects related to computational materials science. The projects are focused on developing models for microstructural evolution in materials. The applications include functional materials, energy materials, materials under extreme environments, and advanced manufacturing. 

 

Gi-Dong Sim's picture

Ph.D. and Post-doc opportunities in ‘Small-scale mechanics and advanced microstructural characterizations’ at Texas A&M

Dr. Kevin Xie's group at Texas A&M is planning to recruit two Ph.D. students and a postdoctoral research fellow starting 2018.

 

The overarching aim of the research projects is to understand mechanics of materials at nano- and sub-micron scales by applying advanced microstructural characterization techniques such as Cs-corrected STEM, TEM- based orientation mapping, EELS, and atom probe tomography. The details of the projects are as follows:

Self-Sealing Cementitious Materials by Using Water-Swelling Rubber Particles

Dear all,

Our group has recently published a paper on self-sealing of cementitious materials by using water-swelling rubber particles as admixtures. This is the first time that such an approach was developed to increase the water-tightness of cracks and therefore enhance the concrete durability.

The paper can be found at: https://www.researchgate.net/publication/319208857_Self-Sealing_Cementit...

Regards

Chiqun Zhang's picture

Computational modeling of tactoid dynamics in chromonic liquid crystals

Chiqun Zhang            Amit Acharya            Noel J. Walkington            Oleg D. Lavrentovich

Motivated by recent experiments, the isotropic-nematic phase transition in chromonic liquid crystals is studied. As temperature decreases, nematic nuclei nucleate, grow, and coalesce, giving rise to tactoid microstructures in an isotropic liquid. These tactoids produce topological defects at domain junctions (disclinations in the bulk or point defects on the surface). We simulate such tactoid equilibria and their coarsening dynamics with a model using degree of order, a variable length director, and an interfacial normal as state descriptors. We adopt Ericksen's work and introduce an augmented Oseen-Frank energy, with non-convexity in both interfacial energy and the dependence of the energy on the degree of order. A gradient flow dynamics of this energy does not succeed in reproducing some simple expected feature of tactoid dynamics. Therefore, a strategy is devised based on continuum kinematics and thermodynamics to represent such features. The model is used to predict tactoid nucleation, expansion, and coalescence during the process of phase transition. We reproduce observed behaviors in experiments and perform an experimentally testable parametric study of the effect of bulk elastic and tactoid interfacial energy parameters on the interaction of interfacial and bulk fields in the tactoids.

Siddiq Qidwai's picture

Employment Opportunity: Program Director, Mechanics of Materials and Structures (MoMS) Program, Division of Civil, Mechanical and Manufacturing Innovation (CMMI), National Science Foundation (NSF)

August 18, 2017

Dear Colleagues:

The Division of Civil, Mechanical and Manufacturing Innovation (CMMI) in the Directorate for Engineering (ENG) announces a nationwide search to fill a Program Director position for the Mechanics of Materials and Structures (MOMS) program.

Formal consideration of interested applications will begin September 15, 2017, and will continue until a selection is made with an intended start date of January, 2018.

Meisam. Asgari's picture

Theoretical and experimental constitutive modelling of soft materials at the nano scale: Cylindrical micellar filaments

We present theoretical and experimental descriptions of the elasticity of cylindrical micellar filaments using micro-mechanical and continuum theories, and Atomic Force Microscopy. Following our micro-mechanical elasticity model for micellar filaments [Asgari, Eur. Phys. J. E 2015, 38(9)], the elastic bending energy of hemispherical end caps is found. The continuum description of the elastic bending energy of a cylindrical micellar filament is also derived using constrained Cosserat rod theory.

Harold S. Park's picture

2 Tenure-Track Positions in Mechanical Engineering, Boston University

The Boston University Department of Mechanical Engineering anticipates two openings for tenure-track junior faculty positions, pending approval by the Provost. These positions are in Emerging Areas of Mechanical Engineering such as Additive Manufacturing, Multifunctional Materials, Photoacoustic Imaging, and Sustainable Energy Systems. 

 

Ruobing Bai's picture

Localized Deformation in Plastic Liquids on Elastomers

Dear Colleagues,

Attached please find our recent paper “Localized Deformation in Plastic Liquids on Elastomers”.

Title: Localized Deformation in Plastic Liquids on Elastomers

Authors: Xavier P. Morelle, Ruobing Bai and Zhigang Suo

Pages

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