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  1. JBlack68

    Von Mises Stress Plot, ABAQUS

    no details so just educated guess could we be looking at pseudo-time? In other words it's not time but load (factor) and 1.0 being the full load (applied to the FEM). Some sort of non-linear analysis (no idea what kind of non linearity if any)
  2. JBlack68

    How to display the thickness of a 2D shell mesh in NX Nastran post-processing?

    in SimCenter, for the 2d mesh collector of interest: Edit Display, tick the 2D display option
  3. JBlack68

    RBE2 equations to establish the force distribution i.e. mpc forces?

    Ok so how does one establish the extra equation needed relating force et dish I guess Small disp applies and rigid rotation
  4. JBlack68

    RBE2 equations to establish the force distribution i.e. mpc forces?

    I think there is a relation between translation (T) and rotation (R) (assumed very small) {Tind} = {Tdep}+{R}{v} where v must be the vector defined by the position of the dependant and each independent node If you consider an RBE3 with 3 dependant nodes working purely in 1 direction then If I...
  5. JBlack68

    RBE2 equations to establish the force distribution i.e. mpc forces?

    To all, Does anyone know a good source/ref for the equations used by (nastran) RBE2 element to get the load distribution assuming a force being applied at the independent node? I remember seeing something in the old msc.nastran manual but cannot find it anymore If one was to set-up a simple...
  6. JBlack68

    Response Simulation Analysis Restraints and Enforced Motion Location

    what the frequency of these RBE elements on each end? Close to zero? There is an example of a beam attached at 1 one and an exciting force at the other end
  7. JBlack68

    Eurocode EC3 Strength Check of the Preloaded Bolt

    is Gamma M7 not the preload factor for high strength bolt - see Table 2.1?
  8. JBlack68

    Element Strain Energies

    check your threshold value. Default value might be 0.001
  9. JBlack68

    What is NLMAX in nastran?

    SOL103 will show all the rigid boy modes
  10. JBlack68

    What is NLMAX in nastran?

    you don't say which version of Nastran you are suing. Anyone reading the QRG will find something along these lines The number of suspected massless mechanisms is determined from the number of high ratio messages. If this number exceeds NLMAX, the number of trial massless mechanisms is reduced...
  11. JBlack68

    Why doesn't the Jacobian increase the number of Gauss points required to integrate when using Quadri

    I do not recall a link between the Jacobian and integration points. The Jacobian is just a scalar value (a determinant of a 2x2 matrix containing the 1st derivative of the shape function if I recall). As stated by E720 it links the perfect/theoretical shape (say a square) to the actual shape of...
  12. JBlack68

    CFD Pressure data to FEM (Nastran)

    in Patran one used to be able to create an interpolated 3D field - did that a long tine ago! [ol 1] one had to import the CFD mesh making sure that the CFD and structural mesh are as close as possible, create the pressure distribution and apply it to the CFD mehs (one-to-one relation) With...
  13. JBlack68

    Model too stiff!!

    can't access the paper. What is the bearing area you are using to calculate the bearing stress? cant see a 0.25*PI*D^2 on the slides
  14. JBlack68

    PSD response with/without 1 normal mode activated?

    by de-activating I meant not including it in the random response. When you use a modal technic for a random analysis one can select which mode to include. If one calculates N modes then "by default" all N modes are included. With some software (all of them!) one can request for some modes not to...
  15. JBlack68

    PSD response with/without 1 normal mode activated?

    Thanks for the replies & suggestion. I have not checked with a 2dof system. I did the test as I wanted to report the effect (on the rms response) of the mode de-activated. With all the modes selected I get X, with all but 1 mode I get Y. Y/X shows that the mode de-activated represents p% of X...
  16. JBlack68

    PSD response with/without 1 normal mode activated?

    To all, A question about the modal approach of solving response for a random analysis With my test FE Model I de-selected 1 mode and compared the PSD response (acceleration) to a prediction will all the modes. The mode selected has a mass participation of 2% The PSD response with the mode...
  17. JBlack68

    [NASTRAN] Temperature in SOL 101

    you shouldn't have an ENDATA in your include file(s). It should be at the end of the main file. So that's a bit odd to me
  18. JBlack68

    [NASTRAN] Temperature in SOL 101

    do you have TEMP(INIT) = 10000 defined
  19. JBlack68

    Stress Strain Curve From Theoretical Data

    Ramberg-Osgood springs to mind !

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