Is it possible that S1 and S3 so different?

[Lirock]

Hi,everyone:
I got a question here. A solid model on which just pressure is applied. I think there should be just compressive stress S3, but I got a high S1, which is far away than the yield limite. I don't know how to paste pictures here, so can't make it clearly.Anybody give me a suggetion how to make it?

 

[cspkumar]

A detailed description of the solid model (plate?, rod?) and the applied load will be helpful here. You can display the stress vectors using "plvect" to gain further insight. I don't know how to attach pictures either.