A "normal modes" analysis neglects damping and produces real eigenvalues and vectors. If damping is included (assuming the damping is less than critical) the eigenvalues and vectors come in complex conjugate pairs. If you look at the last part of chapter 10 in "Funamentals of Structural...
I got word from the Femap folks that this is a bug in 11.2 when a academic license is used and will be fixed in the next update in about a month. Yes, compositesecurves, the neutral file is a work around for now. Thanks for your input.
I am using an academic license and this problem may be related to that.
Just installed Femap 11.2 and tried to open files from the previous version (11.1.2). I get the message
"Unable to open Student Version Model in this version"
and then on the next window I get
"Unable to start Database...
Fixed interface modes and constraint modes are used in component mode synthesis (Super elements in Nastran). These two types of modes are the Ritz vectors for the Craig Bampton method. Other types of modes can also be used. Guyan reduction is based on constraint modes.
Has someone have an example of how use solution "21 Transient Heat Transfer" in Femap. I have done steady state heat transfer solutions before but I am having trouble getting the transient solution to work. A simple tutorial showing steps would be great.
If you did define contact surfaces, the linear static solution requires an iterative solution process (and technically is a nonlinear solution). A normal modes analysis requires a linear model. I believe if contact surfaces are present, the use a default setting which is probably no contact...
A colleague regularly attributes differences between measured results and predicted results from plate/shell element models as due to shear locking (either in plane or through the thickness). We are talking about nonlinear models with many possible modeling errors. My experience has been that...
Did you check the Output Report (under the view menu) and the CANDE Log File? It appears there is an error in the imput but without some program diagonistics, finding it may be difficult.
Paul - from your description of the model, I suspect your model would require a level 3 analysis, were every detail of the model needs to be specified. For a new user, that would take a great deal of effort.
Doug - I don't believe the source code for the current version is available for...
Did you provide a compression stiffness value in the gap element property table? In Advanced nonlinear, it works as a nonlinear spring and needs the user to provide appropriate tension and compression stiffness values.
I am getting an error installing Abaqus 6.9 on my new laptop. It uses Windows 7 Ultimate with 64-bit OS. When I try to install the program (the documentation go on OK) I get:
?
WARNING: Unexpected output from Abaqus executable findWinVer.exe.
ERROR: This computer's platform is Windows/x86-32...
As I recall, the analytical solution by Roark also neglects transverse shear deformations which are included in the elements discussed. If that is true, one could expect a well refined mesh to give slightly larger displacements, as noted by IDS.
