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  1. Bhat165

    Averaging results across materials

    SWComposites: Can you elaborate on your comment? Thanks.
  2. Bhat165

    Elastomeric Bridge Bearings with

    You are using an element which is activated depending on deoformation of teh structure, that means, your problem is of nonlinear in nature. At present I dont know if any software can handle this. If you write code, its straight forward.
  3. Bhat165

    Averaging results across materials

    About the first point made by Marc: Its true that fully bonded material has same strain but different stress, so in reality averaging does not make sense. But for that you need to model the interface seperately as suggested by corus, which is not possible as Martin99 said, in that case average...
  4. Bhat165

    Averaging results across materials

    To further clarify: Let element 1 of material 1 has a common boundary with element 2 of material 2 and let the boundary nodes are x and y. When you calculate stresses in gauss points of E1, you use M1 and extrapolate to nodes x,y. Similarly when you calculate stresses in gauss points in E2, you...
  5. Bhat165

    Averaging results across materials

    I am not sure why you want to average the result across the material boundary. Why cant you use individual material properties to calculate stresses in individual materials? Generally stresses are calculated at gauss points and extrapolated at nodes. So, if you use gauss point stresses you can...
  6. Bhat165

    FEA Model versus Actual Results

    rpm63, Did you try with different number of elements as well as different order of elements to see if the result converged to some value? If that is not the problem, to my mind, the three possible reasons behind this could be: (i) inaccurate material properties, (ii) inaccurate simulation of...
  7. Bhat165

    MATLAB TOOLBOX ON FINITE ELEMENT

    Can any one tell me if there is any Finite Element Toolbox available in Matlab (not a third party product)? It appears to me that it does not have. Thanks. Sudip
  8. Bhat165

    Large Stiffness Matrix

    Your problem seems to be a memory storage problem. You should try to use banded or skyline solution technique to see if there is any difference. I use Matlab, I use variable memory allocation. You can also do teh same in Fortran 90 as well as in C/C++. I also clear momory of many variables which...
  9. Bhat165

    FEA Programming

    bkal, You are right, I forgot to mention that book. It has a chapter on basic programing techniques. Also in every chapter it gives coding side by side with theory. You also know how to code nonlinear problem efficiently with this book, since this is basically a nonlinear fem book. Great book...
  10. Bhat165

    FEA OF RUBBER LIKE MATERIALS

    Hello GSC, Thanks so much for information. I would like to know what level of strain you were experiencing with your neoprene? The reason why I am asking you this is: for small range of strains (less than 1%, say) the curve behaves linearly. True rubber always shows nonlinear curve at higher...
  11. Bhat165

    FEA Programming

    It all depends upon your ram and other configuration. If you run in x386 system, probably it will take a lot of time depending on your problem. For linear system, with P4 processor or above, it should take few seconds. But I believe as a good programer who is learning new methods, he should try...
  12. Bhat165

    FEA Programming

    You should look for the book Numerical Recipes in Fortran or C for banded solution. visit www.nr.com. Or search in Amazon. For other fem coding, you should follow your own algorithm, there is no "The" algorithm for fem, all depends upon your requirement. Read the theory first and start...
  13. Bhat165

    FEA OF RUBBER LIKE MATERIALS

    Thanks EnglishMuffin.
  14. Bhat165

    FEA OF RUBBER LIKE MATERIALS

    E K = -------. so when pr -> 0.5, K -> infinity, that means 3(1-2*pr) incompressible. Is this correct? E From the relation G = -----, we see that for E>0 and G>0, 2(1+pr) the lowerbound of pr is...
  15. Bhat165

    MODELING MOVING LOAD WITH ABAQUS

    Hi Everyone, I am trying to model a moving wheel load on a surface using abaqus. The problem consists of modeling a tire and surface and proviidng contact between then, while giving tire an initial rotation. Since modeling a tire with tire pressure itself is a tough job, I tried to get an...
  16. Bhat165

    FEA OF RUBBER LIKE MATERIALS

    Hi Everyone, I just wanted to inform that Abaqus ran excellent with hyperelastic model. The only doubt I have till now is that: Abaqus is not asking for a Poisson's ratio for hyperelastic model. Is it calculating the Poisson's ratio from input data or assuming something close to 0.5 (say...
  17. Bhat165

    FEA OF RUBBER LIKE MATERIALS

    Hi everyone, I am now using ABAQUS for hyperelastic modeling of rubber. But still I have one doubt. My problem consists of a layer of rubber sandwiched between two different materials of different elastic modulus and the whole system is under surface traction, which is compression in nature...
  18. Bhat165

    ACCURACY OF STRESS CALCULATION - WHICH METHOD IS BEST?

    Hi Ed. R, Can you explain a little bit by what do you mean by "depending on how it is done"? Thanks. Sudip
  19. Bhat165

    ACCURACY OF STRESS CALCULATION - WHICH METHOD IS BEST?

    Hi, I am doing a few coding on FEA using isoparametric continuum elements. I have read several books about the method of calculation of stress after the solution for displacement is available. My approach is: I calculate stress at the gauss points and then interpolate to the nodes using the...
  20. Bhat165

    calculate cable tension due to wind loading

    If your mesh is made up of fine grids of cable, you can model the mesh as a membrane and analyze the membrane against lateral load (a membrane can only take lateral load when axially stiffened). The initial membrane tension can be calculated from the profile. You can also use fem with this...
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