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Recent content by MToft

  1. MToft

    Reporting Max Stress

    Hi, Are the two radii the same? It might be possible to improve the understanding of what's happening by changing the rads (while keeping them the same as each other). Also, if possible, maybe review the convergence performance, error estimates etc to see what the solver's own estimate of the...
  2. MToft

    WHICH HARDWARE ???

    Hi, I tend to use Abaqus or Nastran but requirements can be pretty similar - 2GHz+, 4Gb RAM, 100Gb memory seem to failry standard minimum levels these days. One trick that helps me is keeping the hard disk reasonably clear and defragmented - if the program can write its temporary files in one...
  3. MToft

    ABAQUS subroutine error, df.exe not found in PATH

    Hi, Have you tried the Abaqus forum, their hotline or the Status Report Search for bugs (on their website)? Alternatively, maybe search your drive for df.exe and copy it to where you're running... Also, LOADS of 6.4 bugs seem to be fixed in 6.5. Good luck!
  4. MToft

    Non Software Specific FEA Training

    Some of the Abaqus courses can be quite generic (especially the earlier parts). DAMT also give general training.
  5. MToft

    Verifying Engineering Analysis

    Hi, The NAFEMS Analysis Management Working Group has recently been looking at the following ASME definitions (re ProbaSci's comments on Modelling/Numerical checking): Verification ========= The process of determining that a model implementation accurately represents the developer's conceptual...
  6. MToft

    surface penetration, how to "correct" it?

    Hi, If you can't refine the slave, can you coarsen the master? The meshes should ideally remain fairly well-matched. Also, are you using penalty or kinematic contact? (Maybe try the other one!) If the penetrating nodes are midside ones, can you try Abaqus 6.5? This seems to help a bit. Is it...
  7. MToft

    Please guide me on which points Gauss quadrature is applied

    Hi, You might find this answered better in textbooks eg Huebner & Thornton, or just Googling for lecture notes that go through the detail. On the other hand, it's simpler just to evaluate everything at Gauss points for consistency. Some smarter codes I think evaluate M and Fint at the nodes...
  8. MToft

    Linear temperature distribution

    Hi, If you're using PDL code then is your front-end Patran? The simplest route may depend on the solver too, eg if it's Abaqus then you can create a function (specifying the spatial variation, eg as a table) and then pick this function when applying your temperature over the area. Other codes...
  9. MToft

    Establishing Material Model

    The short answer is no, I don't think ProMech can handle non-linear materials directly. However, it might be possible to approximate overall average behaviour with a sort of "lumped-parameter" model eg if the average cookie region has 5% porosity then reduce the stiffness, density and strength...
  10. MToft

    Welding distortion simulation

    Adib Becker at Nottingham University, UK, has done a lot of work (inluding with NAFEMS) on weld modelling, tho usually for stresses rather than distortion - maybe have a look at his web pages/Google, ring or email him; I regard him as a bit of a weld modelling "guru" (in as much as anyone...
  11. MToft

    Advise on using spring elements on compression to test stability.

    Hi, I don't think ProMechanica can do this directly, especially not if there's significant sliding/friction. In Nastran we wrote macros to create the necessary array of springs (for a slightly different purpose!). However, the contact pressure might indicate the sort of problem I guess you're...
  12. MToft

    Mat Foundation Design Parameters

    Hi, The spring constants should come from the element area and spring length ie stiffness = modulus * area / length. If this initial model treats the soil as linear, it's worth checking the soil strain (from displacement) to see if there's a risk of non-linear behaviour (depending on whether the...
  13. MToft

    Diplay template... Contour or Element?

    Hi, I generally reckon that a minimum accuracy level is with two Gauss points within 10% of each other at the stress peak (eg 300 and 330MPa) - ideally agreeing to within 1% (or 2 significant figures eg 300 and 304MPa). In these cases the element averaged ("contour") value should be pretty close...
  14. MToft

    Storage tank finite element analysis - fitness for service

    I've used Caesar for pipework but seen Finglow used specifically for pressure vessels (you can hire it) - we used to treat pipework terminations as constraints in Caesar then impose the loads and moments on the vessel model in Finglow. Done some work assessing old pipework and associated plant...
  15. MToft

    ABAQUS Slow on Intel Pentium/Xeon c.f. AMD Ahtlon

    It may be worth checking what pre- and standard-memory are set to in the abaqus.env file, which tells Abaqus how much RAM to use for each job in the directory containing the ENV file. Setting this to 100% RAM can run the risk of "Code 5" crashes if Abaqus then conflicts with Windows...
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