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Updated: 9 hours 48 min ago

8th ICCSM - Abstract Submission Deadline Extended

Thu, 2014-10-30 10:44

In reply to 8th International Congress of Croatian Society of Mechanics – Abstract Submission Deadline Approaching

Due to numerous requests for an extension, the new abstract submission deadline is now 1 December 2014. Also, since an initiative to organize a thematic session during the Congress has been recently proposed to the Congress Co-chairmen, we have decided to offer such possibility to other participants as well. More detail can be found at The new deadline for abstract submission is 1 December 2014. To submit an abstract, please register at Abstract template can be found at After your account has been authorized you will receive an email with login information. Please login at to submit your abstract. You will be notified of the abstract acceptance by 15 January 2015. Full papers should be submitted by 15 April 2015.

Dear Sir,

Wed, 2014-10-29 10:08

In reply to Postdoc in multi-scale modelling of composites vibration response @ Ghent University (Belgium)

Dear Sir,

I would like to know what would be the last date for applying for this position ?

structurally singular

Wed, 2014-10-29 08:54

In reply to my "stiffness" matrix comes out singular?

Hi there,

I have come to find out that the model as described below is "structurally" singular.  Consequently, it appears I have to solve it by finding the Moore-Penrose pseudo-inverse of the final matrix.



Tue, 2014-10-28 01:56

In reply to convergence difficulty

i'm beginner in XFEM-Abaqus.would you please send me the pdf file that is about how to improve the convergence in xfem


thanks a lot

my email

Email me

Mon, 2014-10-27 22:39

In reply to Problems & Solutions :: Molecular Simulations in Mechanics and P

Email me at dibakar_datta[AT] I will send the files. 

Problems & Solutions :: Molecular Simulations in Mechanics and P

Mon, 2014-10-27 18:14

In reply to For Beginners :: Problems & Solutions in Molecular Simulations in Mechanics and Physics ( with Matlab Code & LAMMPS Script)

I could not download "Problems & Solutions :: Molecular Simulations in Mechanics and Physics" file. Could you check it or could you tell me how to download this material?



I have experience with the

Mon, 2014-10-27 09:39

In reply to material nonlinearity

I have experience with the arc-length methods yes. If you have material nonlinearity, you can either use very small arc-lengths which however limits the use of the method. Are you using the classical arc-length method? It works very well with geometrically non-linear problems, BUT for strong slip localisation causing a global snap-back response, it may fail.  Thats why one may have to use either the crisfield method (Cylindrical arc-length method ) which involves a non-linear constraint for the arc-length. But its numerically very expensive.  If such methods are not available, you may have to implement new methods. There are many arc-length methods with the same underlying principle. The method of chen and schreyer (A numerical solution scheme for softening problems involving total strain control, Computers and structures; 37 (6) ,  1990, pages: 1043-1050) is based on using strain as control parameter. You can also check the method by May and Duan (A local arc-length method for strain softening; Computers and Structures, vol 64 . 1997, pages 297-303)These are non-standard methods which you may have to implement by yourself. Hope it helps



quasi/static modelling

Mon, 2014-10-27 06:56

In reply to ANSYS/LSDYNA

i am doing experimental investigation  of springback effect on CFRP .

i wanna do analysis of that process through quasi/static modelling 

kindly guide me ,


Sat, 2014-10-25 14:36

In reply to Sharing an abaqus UMAT using an elastic viscoplastic model for soil


I have a problem with UMAT subroutine usinage.

I wrote a UMAT subroutine for my material and I want to implement it in Abaqus but I don't know how can I do this. How can I introduce this code to Abaqus and run the simulation. I'll be glad if you help me to do this.


Mehran Ashrafi

Congratulations to Huajian

Fri, 2014-10-24 15:05

In reply to Professor Huajian Gao to Receive 2015 William Prager Medal

Congratulations to Huajian for such a distinguished honor! Well-deserved!


Fri, 2014-10-24 12:33

In reply to Professor Huajian Gao to Receive 2015 William Prager Medal

Congratulations to Prof. Gao for the leadership in applied mechanics!

material nonlinearity

Fri, 2014-10-24 10:01

In reply to Hi, There are several arc


In my case there is a material nonlinearity problem, I can not properly impose arc length in nonlinear material. Do you have any experience in it?



Thu, 2014-10-23 18:26

In reply to Strain hardening

Dear Professor Sue,


Firstly, thanks a lot for your very instructive notes. This is very generous of you to share them on iMechanica.

I was windering if I can ask a question regarding the strain hardening model. Is it possible to add the Bauschinger's effect to this strain-hardening model? In that case, the compressive yield stress \sigma_YC will be 2Y-\sigma_YT, where Y is the first Yield stress in tension, and \sigma_YT denotes the new yield stress in tension?

Thanks so much





initial void ratio for soil

Thu, 2014-10-23 03:27

In reply to initial void ratio for soil

I have the same problem. Do you solve that error? If you did please give me some informations!

All the best 

cyclic loading

Wed, 2014-10-22 14:15

In reply to T = 1/10 = 0.1s.  So for


i am modelling a composite plate subjected to a cyclic loading

i wnat to model a 1000 cycle with 10 hz frequency.

 i have some question from you.

is it possible to use static,general as step?

on the other hand , i use  umat subroutine for egradation of properties, i want to have a degraded properties,in each cycle.

is it true that i assme  that every increment is 1 cycle?

and at last, i dont understand what exactly,do you mean in this sentences "Recommendation will be to load in one step and unloading in another step"

can you explain it?



gaussian distribution or Goldak heat source model in ANSYS?

Wed, 2014-10-22 01:33


dear friends.. i am learning FEA on ANSYS for Arc Welding. can anyone tell me how to model Gaussian or Goldak heat source model in ANSYS?

Inquiry about your available PHD positions

Mon, 2014-10-20 04:37

In reply to PhD studentship at URV, Tarragona, Spain

<p>Dar Prof. Huera,</p>
<p>My research fields exactly coincides with your research areas. I sent an email to you yesterday with my CV attached. I will appreciate you if you&nbsp; take a look at my CV.</p>
<p>Thanks in advance</p>
<p>Morteza Alinia</p>
<p>Email: <a href=""></a></p>

hello Mr Jahanshahi

Mon, 2014-10-20 02:54

In reply to Displacement Controlled Analysis

hello Mr Jahanshahi

thank you so much for your attention. 

I will do what you said.


hello   peto24ap

Sun, 2014-10-19 23:22

In reply to Geometric nonlinearity

hello   peto24ap

Why do you use line 4 method for computing internal force? I think this is the problem. Use ordinary method for internal force, Just like the    method introduced in  " introduction to finite elements in engineering" ,by chandrupatla or every other fnite element book, to make your internal force vector.

look for this article "COMPOSITE MATERIALS IN  COMPRESSION " by  Jens Lycke Wind, In this thechnical report you can find an algorithm for Newton raphson.

I used it before for load base problem but i could not write a code for material nonlinearity which is under displacement BC, and displacement control.

Ask me if there is some thing to ask, our ways are similar. maybe we can help each other in the modeling


Hi, There are several arc

Sat, 2014-10-18 14:34

In reply to arc length in delamination

Hi, There are several arc-length methods that could be used. But depending on the level of non-linearity, they may or may not be able to trace snap-back exactly.

Geometrical nonlinearity simple arc-length method should be sufficient. But in case of severe strain localization, you would need a method like the one suggested by

Crisfield arc-length method. Try this one, incase this one does not work, I may have other suggestions.




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