Hello Stress Gurus,

I was reviewing my stress output reports one time and I notice that all my rigid bodies shows a zero allowable stress.I remembered I was asked by my colleague regarding this and based on my understanding this is what i told him.
When we model a rigid body (like valve,flange,etc.) Caesar software increases the thickness to become it stiff. If its too stiff, bending is impossible so it means zero bending stress which therefore means no calculated code stress. Thats why on stress report it is zero value.
Kindly correct me if i am wrong. Thanks in advance.

That psuedo-increase in "t" is only for the determination of the inertia and area used in the stiffness matrix.

The reason the Allowable and the Code stress are both zero on rigid elements is that we don't know the cross section. For 8" Std pipe, what is the thickness of a gate valve? Is this thickness the same from manufacturer to manufacturer? Does the thickness vary from one end of the valve to the other?

Regardless of what these answers are, the rigid body is so much stronger than the pipe, you can't overstress this element without failing the pipe first. So the stresses (either Code or Allowable) are not significant in a flexibility analysis.