When Lame and nu are big number, the result is always zero.

[张嘉宁]

Hi,

I am the new one here, and recently I test a program solving elastic problem considering neumann boundary conditions. So I finish  it on the basis of Step-17 by adding the neumann boundary conditions. I found that wen lame and mu are not large (i.e.  equals to 1 by default), the solution seems right. But when I set the lame and mu to the parameters of stell, the solutions is always zero. Interesting, if the lame and mu are not so large, part of the solution is zero but the other part is not. Anyone know the reason?

Thanks for your time!   

[Wolfgang Bangerth]

Is the solution exactly equal to zero, or just small?

It does make sense that if the parameters become large, the deformation
becomes small if you keep the force the same: after all, if you apply a bit of
force to a pillow made of cloth, you will get a deformation of a few
centimeters. If the pillow were made of steal, you'd get a deformation of only
a few micrometers.

Best
W.

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Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/