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  1. rlnorton

    natural frequency of a pinned beam

    Take a look at Timoshenko's "Vibration Problems in Engineering." In the 4th edition the solution is on page 454.
  2. rlnorton

    Looking for Text Book

    Roy Levy retired from JPL quite some time ago, and died about a couple of years ago.
  3. rlnorton

    Rectangular Plate, large deflections

    Timoshenko's "Theory of Plates and Shells" has a chapter on large deflections of plates, with a fair amount of coverage on rectangular plates.
  4. rlnorton

    Software To Create Logarithmic Files

    I'm using Excel 2000, but as I recall all that I do works on earlier versions as well. The only fundamental limitation I've found is that the min & max values for the axes must be powers of 10. At times I'd really like to cut an axis off at 120, and it is required to go to 1000. Other than...
  5. rlnorton

    Software To Create Logarithmic Files

    What is about Excel that doesn't work for you? I've had pretty good luck with it, although sometimes it is non-intuitive. Bob
  6. rlnorton

    natural frequency of cylindrical shell with edges simply supported

    The best reference for shell vibration is "Vibration of Shells" by Arthur Leissa, published in 1973 as NASA SP-288. This had been out of print for years, but the Acoustical Society of America is now reissuing this and the companion "Vibration of Plates". See...
  7. rlnorton

    MSC.Nastran Elements Manual

    The best source that I've seen is the book by Richard MacNeal (co-founder of MSC), "Finite Elements: Their Design and Performance." This is published by Marcel Dekker, and was written in 1994. If you are in the USA, this is available from the SAE (www.sae.org) for $29. MacNeal gets...
  8. rlnorton

    Geometric stiffness matrix for a beam element

    The best published writeup I've seen is in "Theory of Matrix Structural Analysis" by J.S. Przemieniecki, pp 388-391, McGraw-Hill, 1968. His derivation is for a 2D beam (6 DOF), but is easily extended to 3D (12 DOF). I've successfully used this to determine beam buckling as well as...
  9. rlnorton

    Engineers Using Macintosh Computers...

    For those looking for MSC/PAL on the Macintosh you might look at LapFEA (www.lapcad.com). My recollection is that LapCAD bought the rights to MSC/PAL and integrated the analysis capability into LapCAD. Gurt continues to support the Macintosh platform, and has pretty reasonable pricing...
  10. rlnorton

    Reading NASTRAN output file .f06

    bradh has the right idea. The punch file is very simple to read. It is ASCII by default, not binary, so writing a program to read it is a snap. Depending upon what you're looking for the print file (.f06) is easier for a human to read, of course, and you should try a simple run with both...
  11. rlnorton

    How 'accurate' is FEM software?

    You're right -- that is quite a thread! Regarding the comment about "no better than 35%", this needs better definition to support such a sweeping claim. Firstly, there is a significant difference between exact elements (truss and beam) and elasticity approximations (plates...
  12. rlnorton

    From Excel data to 3D drawing anyone??

    You might want to take a look at POV: http://www.povray.org/ POV is an open-source rendering program. It's been awhile since I've used it, but as I recall you describe objects using the x,y,z locations of the grid points (using FEM-speak). If you've got all the grid points in your Excel...
  13. rlnorton

    Assembling Stiffness Matrices

    A very nice open source program that has many Matlab features in Scilab, http://www-rocq.inria.fr/scilab/. They have an executable for Windows (and other OSs).
  14. rlnorton

    Should We Use Free Software

    Keep in mind that even with expensive commercial software no company stands totally behind the results. Every agreement that I've seen says that the user is responsible for validating the results. The software developers naturally don't want to be sued when your structure fails, whether the...

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