Why the strain is not linear in a linear analysis?

pianpianc

Hello,

 

I have a 3D solid brick elements on top of the 2D shell elements, and the equivalent tool was used to combine the two different element to be one piece. However, I created a strain plot, and the strains were not linear, it has a jump at the location where the two different element connect.

Is anyone have any ideas about what is wrong with my model?

 

Thank you,

PianPian

Simon Križnik

Hi,

 

actually, there is nothing wrong with your model. The difference in strain between solid and shell elements is because by default stresses and strains are output at the element center only. In the case of bending there is higher stress and strain at outer surfaces or edges. If we want to find the stress/strain at those locations we usually apply a membrane/rod elements skin of negligible thickness to measure those quantities. 

 

For more details (its about stress but the same applies to strain):

 

 

Attached is the simple cantilever model where I requested stress & strain output at corner locations. As you can see, there is no discontinuity in strain values.

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