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  • Users: izyk
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  1. izyk

    Bonding process modelling

    Hi I have a problem with bonding process modelling to obtain thermal stress resulting in deformation of the structure. The device contains two materials that are bonded in a specific temperature. Then the device is cooled to ambient temperature. Due to difference of thermal expansion...
  2. izyk

    ISTRESS and TRANS126 element

    it works, thanks
  3. izyk

    ISTRESS and TRANS126 element

    Hi Is there any posibility to perform a simulation with trans128 element and apply initial stress to other element (like shell181)? Ansys v10 gives an error that istress command can be used only for specific elements (shell181 included). However I apply a stres only on shell element, not on...
  4. izyk

    Residual stress

    Found a solution. A nonlinear simulation must be used.
  5. izyk

    exporting data from ansys

    In GUI: List -> results -> path data -> file -> save as.. In script: /OUTPUT,filename,extension, ! redirects output to file PRPATH,_UX,_UY ! prints path data /OUTPUT ! resets output redirection but both solutions result in text file divided into pages. The...
  6. izyk

    Residual stress

    Probably I've found the solution. To describe the residual stress due to difference between thermal dilatation coefficients in layers, one use Sx and Sy because the membrane is stretched / squeezed only in XY plane. Simulation (using solid elements) of silicon membrane 300x300x5um with oxide...
  7. izyk

    Residual stress

    Ok, now it works. The first problem was this what jiligeo have noticed. The second thing is that the initial stress is applied to a material. So i had to simulate a membrane with a substrate. Another question. Does anybody know what values od stress should i use to simulate a membrane made of a...
  8. izyk

    Residual stress

    There is no INISTATE command in Ansys v10.
  9. izyk

    Residual stress

    Hi I don't know how to apply a residual stress to a membrane. I used a ISTRESS command but it didn't affect on membrane deflection. Here is a script i've used: FINISH /CLEAR Lm=300 Wm=300 Tm=5 b=30 /PREP7 ET,1,SHELL181 R,1,Tm MP,EX,1,130e+9*1e-6 MP,DENS,1,2330*1e-18...
  10. izyk

    Writing path data to file

    Hi How to write path data results to a text file using command line? I used PASAVE command but it writes in coded file so after that it's useless for me. I would like to have a file like this one created in GUI: List -> results -> path data -> file -> save as.. but without following lines...
  11. izyk

    Modal analysis with loads

    Ok, i didn;t know that for plates K depends upon P. But now i can't receive results for electrostatic pressure. Because of unsymmetrical matrices i have to use unsymmetric extraction method. But it gives no results in results summary. The same for a membrane without load. p.s. i don't want LD...
  12. izyk

    Modal analysis with loads

    ok, it worked but i obtained results different from theory. I'm simulating a circular membrane clamped on edge without damping, large deformation and stress stiffening. Such system can be expressed by following formula: mw'' + Kw = P*S where: m - mass, K - spring constant, P - external pressure...
  13. izyk

    Modal analysis with loads

    Hi I dont know how to perform a modal analysis with loads. I'm trying to find modes frequencies of membrane under pressure but applying a pressure changes nothing, membrane still oscillate around zero deflection. I know that constant load doesn't change frequencies but later i want to apply an...
  14. izyk

    Electrostatic simulation

    Hi I'm trying to develop an analytical model for membranes under electrostatic pressure. The classical law governing membrane's behavior is (developed by Timoshenko, "theory of plates and shells"): laplacian^2 (w(x,y)) = P / ( D*h^3 ) w(x,y) - membrane's deflection P - applied pressure D -...
  15. izyk

    Pull-in voltage for square membrane

    Hi I've got a problem with electrostatic simulation. I've simulated square memrane 300x300x5um, under the electrostatic force using TRANS126 element. (see the script below) I took all voltage values from 0V to pull-in. I've also calculated the pull-in voltage using an equation: Electrostatic...
  16. izyk

    Solution not converged..

    Hi I have a problem with electrostatic simulation. I'm trying to simulate a membrane with an electrode below. Performing a simulation in some range of voltage gives following results: Let's assume that for 15 volts that membrane touches the electrode. In range 0-13V results are correct, in range...
  17. izyk

    transducer problem

    Hi I'm trying to simulate a membrane under an electrostatic field using transducers. If i generate transducer elements for each node of the membrane in one step, it works good (the results correspond to the theoretical equation). Now I'm trying to generate two levels of transducers. I generated...
  18. izyk

    parametrical simulation

    I would like to store Z displacement of node 30 each time in results2.dat only FINISH line is stored (amount correspond to steps value) --------- steps=2 *dim,result,array,steps - two steps *dim,volts,array,3 - array with different load values volts(1)=10 volts(2)=100...
  19. izyk

    parametrical simulation

    I would like to perform one simulation which has a few steps: - one load is changing and after each step result from one node i stored in file How to do this using loops? thx
  20. izyk

    Air and liquid modeling

    Hi I have to simulate a pressure sensor built on closed membrane. In the cavity there is the air (atmospheric pressure) and the sensor is surrounded by liquid. I would like to perform a transient analysis (i'd like to know the sensor response to ambient pressure changes). How to model the air in...

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