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PhD positions at George Mason University, ME Department (Controls in brain-computer interface & healthcare)

Applications are invited for PhD positions at the Algorithms in Medicine and Neuro-Technology Lab (AIMAN Lab) in the Department of Mechanical Engineering at George Mason University, Fairfax, VA.

Research
The AIMAN Lab pursues fundamental breakthroughs in biomedical cyber-physical systems. The lab’s primary research focuses on application of mathematical modeling, controls and estimation theory, and machine learning in health information technology including decision support and automated care systems, with the intention of improving the quality of healthcare, as well as brain-computer interfaces to bring neuro-enhancements to the daily consumer.

Application
Interested researchers with passion in digital healthcare and neuroscience are encouraged to send their CV to Dr. Ramin Bighamian at rbighami@gmu.edu.

Qualification
Experience in controls engineering, estimation theory, machine learning, MATLAB
A Master's degree in mechanical engineering, electrical engineering, or other related disciplines.

Solving incompressible finite elasticity without tears

Solving incompressible elasticity has been quite challenging numerically. The conventional approach for handling incompressibility is the so-called penalty method. A volumetric energy term enters into the strain energy and penalizes the volumetric deformation. One straightforward issue is that the penalty parameter goes directly into the tangent matrix. The bigger the penalty parameter, the worse the condition number of the matrix. This is really a manifestation of the ill-posedness of theories based on the Helmholtz free energy, in my opinion [3].

Ruobing Bai's picture

Tearing a hydrogel of complex rheology

Dear colleagues,

I would like to share with you our latest paper focusing on the fracture of hydrogels of complex rheology.

 

Title: Tearing a hydrogel of complex rheology

Authors: Ruobing Bai, Baohong Chen, Jiawei Yang, Zhigang Suo*

Abstract:

Mike Ciavarella's picture

review paper: The role of adhesion in contact mechanics

Journal of The Royal Society Interface 16(151), February 2019.    DOI: 10.1098/rsif.2018.0738

Michele Ciavarella Junki Joe Junki Joe Antonio Papangelo James Richard Barber

Antonio Papangelo's picture

The role of adhesion in contact mechanics

Just published in Journal of the Royal Society Interface

Ciavarella M, Joe J, Papangelo A, Barber JR. 2019 The role of adhesion in contact mechanics. J. R. Soc. Interface 16: 20180738. http://dx.doi.org/10.1098/rsif.2018.0738

Abstract

PhD positions in Controls are available at George Mason University

<p>Applications are invited for PhD positions at the Algorithms in Medicine and Neuro-Technology Lab (AIMAN Lab) in the Department of Mechanical Engineering at George Mason University, Fairfax, VA. "Research" The AIMAN Lab pursues fundamental breakthroughs in biomedical cyber-physical systems.

Postdoctoral position in computational damage geomechanics

A postdoctoral position in the field of Computational damage geomechanics is open at Université Côte d'Azur.

This project is the result of a collaboration between Geoazur at Université de Nice, the Centre for Material Forming (CEMEF) at Mines ParisTech and the Laboratoire Jean-Alexandre Dieudonné (LJAD) at Université de Nice.

Question about implicit creep subroutine in Abaqus

The implicit implementation of creep in abaqus requires dh/d(\delta \epsilon_c ) as Jacobian in Newton-Raphson's iteration. The derivative can be expanded as shown in the figure attached. The term dh/dq, the one underlined by a green stroke, is expected to be provided by users through specifying DECRA, whereas the term dq/d(\delta \epsilon), underlined by a red one, is confusing me. It seems that that term is computed by Abaqus but I have no idea how it is done. The same question applies to the last derivative on the right hand side.

A tutorial on Bayesian inference in mechanics

http://hdl.handle.net/10993/37698

Hussein Rappel's new paper is out.

— STEPHANE BORDASlegato-team.eu Try out MuLib https://mulib.azurewebsites.net/ 

35 PhD positions open - apply online

Cohesive element modelling problem in ABAQUS

Dear All,

I am modelling a 3 point bend specimen with Cohesive elements tied to the upper and lower halves of the specimen in 2d.

The problem is that the CZ elements perform properly only for a combination of element sizes, i.e. a combination of element size of structure and CZ elements, for instance in my case the structure/specimen element size is 0.2mm and CZ is 0.001 or 0.002. For any other combination the adjacent elements bend as shown in the attached image.

I will be glad if someone could explain this behaviour and the solution.

KevinGE's picture

Fast-Response, Stiffness-Tunable Soft Actuator by Hybrid Multimaterial 3D Printing

ttps://onlinelibrary.wiley.com/doi/full/10.1002/adfm.201806698

Fast‐Response, Stiffness‐Tunable Soft Actuator by Hybrid Multimaterial 3D Printing

Yuan-Fang Zhang, Ningbin Zhang, Hardik Hingorani, Ningyuan Ding, Dong Wang, Chao Yuan, Biao Zhang, Guoying Gu,* and Qi Ge*

Emilio Martínez Pañeda's picture

Steady-state fracture toughness of elastic-plastic solids: Isotropic versus kinematic hardening

I hope some of you may find this work interesting. We show that kinematic hardening effects play a significant role in monotonic/static fracture.

Steady-state fracture toughness of elastic-plastic solids: Isotropic versus kinematic hardening

K.J.Juul, E.Martínez-Pañeda, K.L.Nielsen, C.F.Niordson

Engineering Fracture Mechanics, 207, pp. 254-268 (2019)

Volume 207, 15 February 2019, Pages 254-268

peppezurlo's picture

Nonlinear elasticity of incompatible surface growth

In this manuscript with Lev Truskinovsky, we developed a new nonlinear theory of large-strain incompatible surface growth. Surface growth is a crucial component of many natural and artificial processes from cell proliferation to additive manufacturing. In elastic systems, surface growth is usually accompanied by the development of geometrical incompatibility leading to residual stresses and triggering various instabilities. Here we developed a nonlinear theory of incompatible surface growth which quantitatively linkes deposition protocols with post-growth states of stress.

Harold S. Park's picture

Designing Highly Stretchable Kirigami Using Machine Learning

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.121.255304

Accelerated Search and Design of Stretchable Graphene Kirigami Using Machine Learning

P.Z. Hanakata, E.D. Cubuk, D.K. Campbell and H.S. Park

Zhaohe Dai's picture

Strain Engineering of 2D Materials: Issues and Opportunities at the Interface

In this progress report, we reviewed recent advances in strategies for applying mechanical strain into 2D materials and recent state‐of‐the‐art characterizations of interface mechanics for 2D material–substrate systems.

Zhengwei Li's picture

A biohybrid valveless pump-bot powered by engineered skeletal muscle

Pumps are critical life-sustaining components for all animals. At the earliest stages of life, the tubular embryonic heart works as a valveless pump capable of generating unidirectional blood flow. Inspired by this elementary pump, we developed the first example of a biohybrid valveless pump-bot powered by engineered skeletal muscle. Our pump-bot consists of a soft hydrogel tube connected at both ends to a stiffer polydimethylsiloxane (PDMS) scaffold, creating an impedance mismatch.

Antonio Papangelo's picture

On unified crack propagation laws

The anomalous propagation of short cracks shows generally exponential fatigue crack growth but the dependence on stress range at high stress levels is not compatible with Paris’ law with exponent m=2. Indeed, some authors have shown that the standard uncracked SN curve is obtained mostly from short crack propagation, assuming that the crack size a increases with the number of cycles N as da/dN=H\Delta\sigma^h where h is close to the exponent of the Basquin’s power law SN curve.

mohsenzaeem's picture

A Review of Computational Modeling Techniques in Study and Design of Shape Memory Ceramics

Shape memory ceramics are a unique family of shape memory materials with a wide variety of applications, such as ultra-high energy dissipation and high-temperature actuation. Along with significant progress in the experimental study of zirconia-based shape memory ceramics in recent years, computational simulations have exhibited powerful capabilities in revealing nano/microstructure-dependent deformation and failure mechanisms in these materials.

Arash_Yavari's picture

Nonlinear Mechanics of Accretion

We formulate a geometric nonlinear theory of the mechanics of accretion. In this theory the reference configuration of an accreting body is represented by a time-dependent Riemannian manifold with a time-independent metric that at each point depends on the state of deformation at that point at its time of attachment to the body, and on the way the new material is added to the body. We study the incompatibilities induced by accretion through the analysis of the material metric and its curvature in relation to the foliated structure of the accreted body.

Regina's picture

PhD and Postdoctoral Research Positions Available Immediately at the University of Haifa, Israel

Project title: Dynamics of methane bubbles ascent in fine-grained aquatic sediments. The project implies conducting modeling and simulations in the field of solid mechanics/linear elastic fracture mechanics.

 

This study aims at:

Matt Pharr's picture

In-situ measurements of stress evolution in composite sulfur cathodes

Owing to their enormous capacities, Li-S batteries have emerged as a prime candidate for economic and sustainable energy storage. Still, potential mechanics-based issues exist that must be addressed: lithiation of sulfur produces an enormous volume expansion (~80%). In other high capacity electrodes, large expansions generate considerable stresses that can lead to mechanical damage and capacity fading.

noushadbinjamal's picture

ParaDis : Discrete Dislocation Dynamics Simulation

Choose a channel featured in the header of iMechanica: 

Forum to discuss all about use of ParaDis in discrete dislocation dynamics simulation

 

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