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Chris Yakacki's picture

Journal Club: Overcoming Challenges in Mechanically Actuating Liquid-Crystalline Elastomers

Smart materials are designed to have a controlled response to external stimuli. Shape-memory polymers (SMPs) are one of the most well known classes of mechanically active smart materials and have experienced an incredible amount of research attention over the last decade. They are able to recover programmed deformations when heated above a thermal transition; however, are generally considered a one-time event. Liquid-crystalline elastomers (LCEs) are another class of actively moving polymers; however, these materials can demonstrate reversible and repeatable shape memory without the need for “re-programming” after each actuation cycle.

Pradeep Sharma's picture

Electrets in soft materials...

This work---whose abstract appears below, has been accepted for publication in Phy. Rev. E: http://journals.aps.org/pre/abstract/10.1103/PhysRevE.90.012603

Transverse shear stresses in Reissner Mindlin theory

How is it possible to obtain the transverse shear stresses correctly, not constant, by Reissner Mindlin theory?

Equilibrium equation would be the first solution, but, once the second derivatives of bilinear shape functions are zero, no results is appeared.

 

Thanks in advance for any help!

Virtual Special Issue: 'Outstanding research contributions in the area of nonlinear continuum and computational mechanics'

The 2014 Nathan M. Newmark Medal was awarded to Professor Herbert A. Mang at the annual ASCE Structures Conference, which took place in Boston, April 3–5, 2014. Professor Mang was awarded the Newmark Medal for his outstanding research contributions in the area of nonlinear continuum and computational mechanics that clarified the cause of collapse of important concrete structures and quantified the influence of the initial post buckling behavior of metallic structures.  

 

Ask for comments on my results from unit cell model of MMCs

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Dear friends,

Could anyone be kind to share some comments on my interesting results? It is my first time to post a topic, hope to communicate more with the members here.

Ultra-Strong Collagen-Mimic Carbon Nanotube Bundles

 In spite of worldwide research, carbon nanotubes (CNTs) still have not fully realized their

 original promise as ideal reinforcements for composite materials due to a number of

 challenging issues such as weak interface, poor dispersion, misalignment and lack of optimized

 design. Here we propose a bio-inspired structure of CNT bundles with controllable

 crosslink density and staggered pattern of organization that mimic the architecture of

 natural collagen fiber. Molecular mechanics (MM) simulations show that, under tensile

Elastic Bounds of Bioinspired Nanocomposites

 Biological materials in nature serve as a valuable source of inspiration for developing

 novel synthetic materials with extraordinary properties or functions. Much effort to date

 has been directed toward fabricating and understanding bio-inspired nanocomposites

 with internal architectures mimicking those of nacre and collagen fibril. Here we establish

 simple and explicit analytical solutions for both upper and lower bounds of the elastic

 properties of biocomposites in terms of various physical and geometrical parameters

MAXPS Damage

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Hi everbody,

 

I am trying to study about carck propagation in a material. The part is 2D deformable and I am going with XFEM for the analysis. 

Can you please tell me how to calculate the MAXPS damage under Damage for Traction Laws?

 

Elastic Modulus of the material: 0.031 (Newton per micrometer square)

Load: 0.15 um displacement in the 'x' direction = 1.2245e-3 N in the x direction

 

I am using Abaqus /CAE 6.10

 

Any kind of help will be appreciated.

 

Thanks

Amit Pandey's picture

Seminal research work: in-situ mechanical testing under electron microscope

A lot work has been done/published in the area of in-situ mechanical testing using electron microscopy. Please list which, according to what you feel has had a significant impact. Here are two in my opinion:

 Uchic, M. D., Dimiduk, D. M., Florando, J. N., & Nix, W. D. (2004). Sample dimensions influence strength and crystal plasticity. Science, 305(5686), 986-989.

Displacement Controlled test using Boundry Condition Module in ABAQUS

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Salam everyone,

I am working on Modeling of a Brick Wall Panel under reverse cyclic load with a concrete lintel at the top.

i need help regarding displacement controlled test in abaqus. there are a total of 24 cycles . . . first four cycles are force controlled (whose frequency is 1/60Hz) and the rest 20 are displacement control (whose frequency is 1/120Hz) . . . the following is the data file . . .

     OPTIONS BEING PROCESSED
   ***************************

Looking for a Postdoc position in the filed of vibration aided fault diagnosis

I am going to finnish my Ph.D. of mechanical engineering with a thesis in the field of vibration assisted fault diagnosis in about 3 months. My main field of research is vibration and I have worked extensively on gear systemes vibration modeling and diagnostics. 

Currently I am looking for a postdoc position at which I can continue my researches in the abovesaid fields.

my Email address is b_hoseini@kntu.ac.ir

Thanks

How to plot crack growth with time in Abaqus

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Hello,

 

I have modeled a 2D plate with sigle edge crack in Abaqus software. I want to plot crack growth with time. Kindly help.

 

Thanks & regards

 

Rajwinder Singh

Email: rajwinder87@gmail.com 

Andres Lahe's picture

EST method with GNU Octave

The EST method -- http://staff.ttu.ee/~alahe/ESThtml/ESTmethod.html -- is a general computational method, for solving boundary value problems for the structural analysis of frames, beams, and trusses. Differential equations are considered here together with a set of boundary conditions.  Compatibility equations for joint displacements and equilibrium equations for member end forces at joints serve as boundary conditions.

Fan Xu's picture

3D finite element modeling for instabilities in thin films on soft substrates

Spatial pattern formation in stiff thin films on compliant substrates is investigated based on a nonlinear 3D finite element model. Typical post-bifurcation patterns include 1D sinusoidal, checkerboard and herringbone shapes, with possible spatial modulations, boundary effects and localizations. The post-buckling behavior often leads to intricate response curves with several secondary bifurcations that were rarely studied and only in the case of periodic cells.

Laura De Lorenzis's picture

French-German summer school on "Multiscale modeling of interfaces and avanced solution techniques"

The Graduate School MUSIC offers its second Summer School at the Leibniz Universität Hannover from 8 to 12 September 2014.  This year's summer school on “Multiscale modeling of interfaces and advanced solution techniques" is hosted by the Institute of Continuum Mechanics

Co-simulation engine error,

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I am operating a co-simulation analysis in Abaqus. This a kind of interaction between fluid and solid so I am doing co-execution. Unfortunately, when the program run up suddenly I encounter this error "  Error in job Co-execution-3-Model-1: Co-Simulation errorError in job Co-execution-3-Model-2: The partner program in the co-simulation has issued a fatal error message.

ductility of carbon nanotube reinforced composites.

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HELLO,

I want to know if carbon nanotubes reinforced composites are ductile as I want to do hydroforming process by using ABAQUS or any other metal forming process that can be implemented.

If it is formable than what are values of yeild strength, ultimate tensile strength, plastic strain,etc.

the matrix material is polymer(PmPV).

THANK YOU.

PhD in Mechanical Engineering at United States/United Kingdom/Canada

Im a final year student in Dual Degree(B.Tech in Mechanical Engineering and M.Tech in Intelligent Manufacturing). I want to procure PhD in manufacturing stream. Your suggestions on universities and areas of research are very valuable to me.

How to model fastener with same force-displacement behavior for all translational directions in a plane in Abaqus?

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<p>Hi everyone. I want to model the fasteners connecting a wood sheathing to a steel frame in Abaqus. I want to input the same force-displacement behavior for all translational directions in the plane of the sheathing (like a radial spring). <br /> <br /> I was using spring element type Spring2 (nonlinear) but I could define behavior in only 2 translational directions in the sheathing plane (X and Z). This made my model overly stiff after the elastic range. I read about the RADIAL-THRUST connector element but it does not seem to be the one.

How to model fastener with same force-displacement behavior for all translational directions in a plane in Abaqus?

<p>Hi everyone. I want to model the fasteners connecting a wood sheathing to a steel frame in Abaqus. I want to input the same force-displacement behavior for all translational directions in the plane of the sheathing (like a radial spring). <br /> <br /> I was using spring element type Spring2 (nonlinear) but I could define behavior in only 2 translational directions in the sheathing plane (X and Z). This made my model overly stiff after the elastic range. I read about the RADIAL-THRUST connector element but it does not seem to be the one.

Adjal's picture

Contribution to dynamic behaviour of structures

Most of topics here in this web site treat the physical behaviour of materials, I would like to share my knowledge and my ideas concerned the analysis vibration of materials ( forced and free) for understand the mechanical behaviour of structures

I adress this message to  researcher whom interssting on dynamic of  structures 

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