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tensor

Respected Sir,

                    I want to know the answer of following questions

1) what is tensor?need of it? & its physical signjficance?

2)what is the psocedure to write high order tensor in matrix form?

3)is there any general formula to calculate no. of independent variable in tensor for any dimension? 

Strain softening behavior

hi my friends, i am new in abaqus, i want to use Mohr-Couloumb plasticity to simulate the uniaxial compression of a coal sample, the behavior of coal is stain softening, i want to know how many data points should i use in the hardening menu of Mohr-coloumb plasticity (cohesion yeild stress & Absolute plastic strain ).

you know that the strain sofening bhavior has yield point and peak and then post peak (softening).

when i make the simulation i used 3 data points

Back Stress in Abaqus

Could you please advise if that is correct to select higher number of back stresses (as input) while simulating test results in Abaqus?

It appears to me that the higher number of back stresses (say selecting number of back stresseses in Abaqus >= 5) give me a better fit to the test results. For my case, 5 is an optimal value as increasing it will not affect the results, much.

Thank you.

faculty search

Faculty Position in Aerospace Mechanics/Materials

Department of Aerospace Engineering

University of Illinois at Urbana-Champaign

 

faculty search

Open-Rank Faculty Position in Combustion/Propulsion

Department of Aerospace Engineering

University of Illinois at Urbana-Champaign

 

Zhigang Suo's picture

Theory of dielectric elastomers

In response to a stimulus, a soft material deforms, and the deformation provides a function. We call such a material a soft active material (SAM). This review focuses on one class of soft active materials: dielectric elastomers. Subject to a voltage, a membrane of a dielectric elastomer reduces thickness and expands area, possibly straining over 100%. The phenomenon is being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators.

Amplitude with ABAQUS.

Hi friends,

I am using ABAQUS to model a O-Cell load test for deep pile foundation. I would like to applied the load which gradually increases with time (in second). But, if I apply the load step by step then it may take much time to input the data. I think we can use AMPLITUDE toolset in ABAQUS to define the incresing load (ex.), but I don't know how to apply the load by using AMPLITUDE toolset.

Example I have:

Time(sec) --- Load (kN)

1--- 100

15 ----500

30----1000

etc..

Can you please tell me how to define?

State of hydrostatic stress along shear zone.

Dear all,

          I did a three point bending test on a brittle rod. I observed an oblique fracture (slant approx 45 degrees). It can be an easy conclusion that this 45 deg crack is due to shear failure. But i have the following questions

1. Can a shear band  occur in  bending mode? as in literature very frequently shear bands are reported in pure tension and compression.

How to supply a visualization for the displacement gradient tensor

Hi all, 

[Warning: The writing is long, as is usually the case with my posts :)]

It all began with a paper that I proposed for an upcoming conference in India. The extended abstract got accepted, of course, but my work is still in progress, and today I am not sure if I can meet the deadline. So, I may perhaps withdraw it, and then submit a longer version of it to a journal, later.

Cohesive elements parameters

Dear All,

I modelled a beam with a hole and used cohesive elements on the possible crack plane.

When I run the model in 2D, it works very well and I can get the results pretty good.

Why running the same model in 3D (making 3D model and running it) has caused me a headach for a long time and I can not

get the results?

Any idea highly appreciated,

Thanks,

Parisa

Mohr-Coloumb plasticity model

i am simulating a uniaxial test for coal specimen using Mohr-Coloumb plasticity, there is a friction between the coal sample and the platens, the coal behavior is stain sotening.

i want to know how many points should i use in the hardening table of the mohr-coloumb plasticiy to get a good reults?

 i used 3 points:- the first one is the yield stress and the associated plastic stain, the second one the peak stress and the associated plastic strain the third one is the post peak stress and the assoiacted plastic strain. is that right?

Mike Ciavarella's picture

Benoit Mandelbrot dies at 85

Mandelbrot has passed away last week.  A very interesting  mathematician, who received tenure from Yale only at 75, he has introduced fractals also in fracture mechanics.

Benoit Mandelbrot, Father of Fractals, Dies at 85

Materials Engineer Full time and Internship opening

    There is a new opening (Full time) for Materials Engineer with emphasis upon computational materials design and modeling. Also, there is an opening for Graduate and Undergraduate intership at QuesTek Innovations LLC located in Evanston, IL. Additional details available at www.questek.com

Rajesh

aaam's picture

I need this book (Theory Of Thermal Stresses by Prof. Bruno A. Boley)

Dear Colleagues,

 I need the PDF version of the following book can any one send me

Theory Of Thermal Stresses by Prof. Bruno A. Boley

Please kindly send it to my email address:

amirali1211982@yahoo.com

Research and Development Scientist

A Research and Development Scientist position in developing multiscale-multiphysics computational technologies for composite materials and structures is available immediately at the Multiscale Design Systems, LLC located in New York City. The candidate should hold a doctoral degree in a relevant discipline, such as Mechanical, Aerospace or Civil Engineering. The candidate should have a strong background in multiscale simulations and scientific programming (C, C++, or Fortran).

Jung W. Hong's picture

Postdoctoral research associate position

We have an opening for a postdoctoral scholar in the area of computational mechanics. Specific problems of interest include the nonlocal plasticity, molecular dynamics and meshless methods for continuum damage mechanics. Rich experience of C++, X-windows image processing, and Fortran programming (especially parallel processing) is required. Contact: Professor Jung W. Hong at Michigan State University.  Email: jwh@egr dot msu dot edu.

 

contact element(ANSYS)

Hi

I will model laminated composite and it have contact element at between layers. Can anybody help me for define of contact element(ANSYS) at between layers?

thank you

Liming Jiang's picture

how to set the absolute contact stiffness when considering cohesive zone material (CZM)property

I'm simulating the interface between a steel plate and the fire proof coatings covering the steel plate. The elements i use in the simulation is contact 173 with a material property of debonding,which is defined as cohesive zone model.(CZM)

 CZM in ansys provides  TBDATA such as maximum contact stress,contact at the completion of debonding, but what's the problem is that I failed to set the initial contact stiffness. it's true that ansys provides FKN to define the contact stiffness, but it's just a stiffness factor.

energy deviation in MDS

Any idea why energy deviation between successive steps become a large value during molecular dynamics simulation, when the number of steps is increased?

Applied Mathematics

Eran Bouchbinder's picture

A new postdoc position is available

A new postdoctoral position in continuum mechanics is available at the Weizmann Institute of Science. Candidates should have a strong background in physics and/or theoretical mechanics, as well as experience with analytical and computational methods for solving partial differential equations. Possible projects include the mechanics of frictional sliding, the mechanics of biomaterials, the mechanics of glassy materials and dislocation-mediated plasticity. Highly motivated candidates are requested to send their CV, publications list and statement of research interests to Dr.

npoEM's picture

Rotational DOF for solid elements in ANSYS

Hello colleagues.

I am solving a ring as an axisymmetric solid. I apply displacements and define reactions. According to an experimental data calculated reactions twice larger. We think it because the ring is thin and it is too rigid in solid formulation. Did anyone see solid formulation with a rotational DOF, i mean in any other FEA products?

Cai Shengqiang's picture

Poroelasticity of a covalently crosslinked alginate hydrogel under compression

This paper studies the poroelastic behavior of an alginate hydrogel by a combination of theory and experiment. The gel—covalently crosslinked, submerged in water and fully swollen—is suddenly compressed between two parallel plates. The gap between the plates is held constant subsequently, and the force on the plate relaxes while water in the gel migrates. This experiment is analyzed by using the theory of linear poroelasticity.

Reconstruction of Saved Stiffness Matrix from ADINA

Hi,

I have saved the global stiffness matrix generated by ADINA. the format of data stored is like below:

MAXA ARRAY
        1            1
        2            2
        3            4
        4            7
        5           11
        6           16

        ...

 

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