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-   -   Plane stress and plane strain cases for stress analysis (http://www.cfd-online.com/Forums/openfoam/117186-plane-stress-plane-strain-cases-stress-analysis.html)

Sargam05 May 3, 2013 18:16

Plane stress and plane strain cases for stress analysis
 
Hello everyone,

I am doing stress-stain analysis in a 3D geometry. First I started with solid cube block. In solidDisplacementFoam constant/mechanicalProperties mentions:

rho rho [ 1 -3 0 0 0 0 0 ] 5163;

nu nu [ 0 0 0 0 0 0 0 ] 0.32;

E E [ 1 -1 -2 0 0 0 0 ] 215e+09;

planeStress no;

If I set planeStress to yes, it works for 2D (i.e. X and Y directions) and when I use
planeStress no;

It works for 3D.

I am using following boundary conditions for the solid cube:
tractiondisplacement normal to the top surface (y-direction), bottom surface is fixedDisplacement (y-direction), and other surfaces are considered as free surfaces.
For 2D block deformations will take place only X and Y directions. I have set plane stress to "yes" condition for 2D block.

For 3D solid block, traction loading is in y-direction on top surface (i.e. normal to the top surface), bottom surface is fixed, and other surfaces are considered as free surfaces. Here I have set plane stress to "no" (means plane strain condition).

In both situations, I my OpenFOAM solution matches to analytic solution.

But when I am using loading in z-direction, with following boundary conditions:
front surface (this surface is in z-direction) have traction loading in z direction (i.e. normal to the surface), back surface is fixed, and other surfaces are considered as free surfaces. In this case, I have used both plane stress and plane strain conditions but OpenFOAM solution did not match to the analytic solution.

How I can set this problem? As it says from the definition of plane stress condition that plane stress condition is used when body is subjected to transverse loading. Does in mean z-direction loading or shear stresses in each direction? Which condition would be more suitable for loading in z-direction?

I appreciate if anyone of you have any suggestion.

Best regards,
Sangeeta


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