[Getdp] Linear Elasticity Examples

[m.fenner at gmx.net]

Dear Christophe,

I rerecently discovered the linear elasticity examples in the wiki - and immediately ran into a few problems with the 3D-example.

1. the ukulele.geo produces a number of errors when loading. The variables in the Layers command are missing:

Error   : '/cygdrive/d/MF/Programme/FEM/Problems/Elasticity-01/parts.geo', line 15 : Unknown variable 'Peg'

Nevertheless a mesh can be generated with a few parts of the ukulele missing. Next I completed the ukulele by assigning the missing variables at random.

I tried both meshes with the .pro files but neither gives a solution:

GetDP   : Warning   : Generated system is of dimension zero
..
GetDP   : Warning   : No equations in linear system

2. I also tried a simple model (rectangular beam). I fix the bottom face of the beam and apply a transverse force  either at the top surface or a top edge without further constraints. The solver is hardly converging, just stopping at NB_Max_Iter. The solution gives an "S"-shaped displacement as if there was a z=0 constraint on the top surface. Despite the warning in the Wiki to use the exmples and operators at own risk: Do you have an idea about where this goes wrong? (I shall attach the files.)

Another question: 

>From the Elasticity_3D.pro file I assume that the non standard D1 and D2 operators also work with the Lanczos algorithm. Is that right? I am quite interested in mechanical Eigenmodes. ohyeahq at yahoo.co.jp has sent a patch for the Lanczos functionality recently. But I fear that it shall take me ages to set up all the stuff (cygwin, GSL, LAPACK ...) required - not to speak of implementing the patch and building my own binaries. Do you intend to implement this patch into a distribution soon? I guess I'd rather wait for that. 

Best regards

Matthias

                          

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