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Implicit and Explicit finite element method

i am not clear about implicit and explicit FEM
kindly let me know the difference of two and where to use which one

Help modeling a viscoelastic material in Abaqus

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I'm trying to model indentation of a viscoelastic material in Abaqus.

I have (1) stress-relaxation curves for the material and (2) force-displacement curves for the material from a real indentation experiment.

From this I can readily calculate the elastic modulus (infinite) and the elastic modulus (instantaneous) for the material.

I'd like to fit a Prony series based on this data that I can enter into Abaqus to model the material.

How would I go about fitting the Prony series from the force-displacement and stress-relaxation curves?

ravi-talawar's picture

Modal Frequencies

Hi All

How to find the modal frequencies of a wind turbine blade,

-Ravi Talawar

how to show the stress in the thickness direction when you use the shell element with abaqus


  •      i simulate some process using shell elment, i find the results have big difference between abaqus and lsdyna. the abaqus results always show the stress in the thickness direction is zero. but the lsdyna is not. i don't know why? if some one know that, please give me some suggestions. i heard that the abaqus can not show that stress component. if not, how can i do to calculate that and fill it into the results file (.fil file). thank you!


Problem with my Abaqus Double Layer Composite Identation Simulation

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Hi everyone,


I currently using Abaqus/CAE 6.8. I currently doing my final year
project about indentation test on double layer composite material. The
top layer of the material is Pasta (elastic) and bottom layer is Gel
(hyperelastic). I manage to simulate the model and completed the
process. The stress of the Gel does not change as it undergoes
deformation. As shown in the clip i attached. Any idea to solve this
problem? Any suggestion is welcomed.. Thanks

Right click the indentation.jpg and save target as....

Impact analysis of bus body-ansys ls dyna

I am a  B.Tech student at VIT.Presently doing a project on Impact analysis of Bus body using ansys ls dyna.I am getting many errors.If any one is having complete tuturial about above topic, pls send it to me.



I am facing some problem in ABAQUS. How can i use Vumat subroutine and how can i findout sresses.Please help me

Nonlinear Analysis

Hello,In order to nurture you in an effective manner regarding the Newton-Raphson method I recommend you to consult the excellent treatise of I. M. Smith et al. entitled "Numerical Methods for Engineers ", ISBN-13: 9781584884019.Furthermore this method is elegantly elaborated in Finite Element Formulation in the outstanding book of I. M.

Detonation &knocking

 hello dosto,

               i am studying in B-tech 2nd year (mech.) in DCE . I want to know  about detonation and knocking of fuels in detail.

thank you

shankar Gupta

Elementary Mechanics and Basic Engineering Thermodynamics

I suppose it is acceptable to announce the work I have online to assist students in learning mechanics and thermo.  The site is  Please take a look if you are interested.

boundary value problems

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Hi All, thanks in advance for any replies.

I am currently doing my Thesis on fast stress analysis using the boundary element method and specifically, adaptive cross approximation. I ofter come across the terms "single layer potential" and "double layer potential", i "know" what they are mathematically, i was wondering if anyone could give me an insight into what they mean physically, or just give a simple non mathematical definition? Thanks a lot, Ian.

GOPALAERO2000's picture

Buckling of Stepped column

Hi everyone,

Does anyone have the work experience on stepped column kind of structure?

I would like to know, how to determine the crippling load for stepped column kind of structures? If anyone have the materials pertaining to the subject, please do share (if interested).


Thanks and Regards


M Gopalakrishnan.

Help with wind tunnel experiments

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In our wind tunnel experiments, we have wake survey of a cylinder and boundary layer measurement for a thin flat plate as two experiments. We measure the stagnation pressure(Pt) at points using a pitot tube. We also measure the static pressure of the free stream Pinf.

Jayadeep U. B.'s picture

Symmetry of Infinitesimal (linear) strain tensor

Hello everyone,

 Why do we have the infinitesimal (linear) strain tensor to be symmetric? The reasons, which I have understood so far are:

1. It is defined to be symmetric so that it behaves like a tensor.

2. The stress tensor, which is its energy conjugate, is symmetric, and hence the skew-symmetric part has no contribution towards strain energy.

 Can anyone suggest more fundamental reason(s) for the symmetry of linear strain tensor, like the moment equlibrium leading to symmetry of the Cauchy stress tensor?

Thanks in advance,

Recommendation for a good entry level text book

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Hi all

Zhigang Suo's picture

Learning temperature, pressure, and chemical potential

I have updated sections of my notes on thermodynamics.  A few thoughts on learning are collected here.  Of our world the following facts are known:

Hertz contact question

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Dear all

I'm doing an analysis where i need to evaluate the contact area acoording to hertz theory.

I have a book which shows me every step, except for how to calculate two coefficients, and insteads gives me a table of calculated values. 

For the contact patch dimensions a and b, i get the expression

chenna's picture

Help Regarding PhD opportunities

Hi Suo and other guys,

I am Chennakesava. I am new to this site. I have completed my Masters in Mechanical Engineering from Indian Institute of Technology, Kanpur, India. (IITK) . Year of study is 2006-08. My specialization is Solid Mechanics & Design. Right now am working in GE, India. I want to pursue doctoral degree in the field of Dynamics and Vibrations and related issues like, Rotor dynamics, Smart structures, MEMS, Nonlinear dynamics and Chaos. Its kind of a dream to me. 


Query on transformation representing deformation fo space , change of basis and orthogonal nature

Hello All
I am trying to read the text book Tensor analysis by IS Sokolnikoff and stuck in
chaper 1, there is some confusion in my mind regarding orthogonal transformations,
change of basis and and a transformation representing deformation of space.
Please bear with me if my confusions are unfounded.
1) Is is safe to say that transformation representing deformation of space acts on
vectors where as transformations representing the change of basis acts on
components?. (if yes then the following questions are resolved and need not be
2) Sokolnikoff builds up the reasoning for orthogonal transformations based on
deformation of space (i.e orthogonal transofrmations keep the length of vector

jintting's picture

Strain Energy Derivation

Dear Sirs,

I'm trying to derive an strain energy in a small volume 2a x 2b x 2t.

I can derive "The rest terms are ommited" by myself . 

By the way, I can't derive the DT2 term in the 2nd row of the figure.

Please help with reference or tips.


Jin Kim

Taxonomy upgrade extras: 

Modeling bone and implant

I'm working with multiple meshed items and attempting to cut them using the Instance boolean operation. My parts include parts I've sketched & meshed in Abaqus and a 3D object I imported from MIMICS (.inp file). When I attempt to selectively cut the instances that overlap, Abaqus failed. Any suggestions on the modeling of bone and implant with a reasonable fit in geometry?

Composites modeling

Hi i want to model a compsoite shaft of glass/epoxy .i am having all material properties .i want to know how to model it .and in another case there is adhesives between the two.



Mehdi Naderi's picture

Cyclic Plastic Dissipation Calcualtion in UMAT

During Fatigue temperaure of materials increases due to plastic deformation.  I am trying to calcualte plastic dissipation in UMAT and use it as heat source in HETVAl to get temperature rise.  I do not know how to add plastic dissipation calculation in UMAt.  I am wondering if some body  give me an example which is done close to what I want to do.

suggestion on a project.............

   hii every one ... i am an  undergraduate student in mechanical enggineering . can any 1 suggest me a good project which includes  1.both computer oriented and also lab oriented project.

2.  also a  project in fatigue analysis.


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