Summation of element volume not giving expected output for axis-symmetric case

[bigmanrunning]

Hi Guys,

I have a simple, 2D FEA model that is a square of size 6, axis-symmetric CAX4R elements, and there are symmetry conditions applied along the radial and axial directions. I am integration the stress and strain tensors over the volume of the simulation and found that the sum of the element volumes are different than what I expect by a factor of 3.

For instance if I have a square of size 6 the area is 36 and if I revolve it around an axis to make a cylinder I would just multiple by 2pi to get ~226. The summation of the element volumes gives for this case ~678 - exactly 3 times what I expect. What am I missing?

Thanks

 

[bigmanrunning]

And it is off by a factor of 3 because I messed up the calculation of the area of a cylinder...