Hello Guys,

I have an question . How ceasar 2 Convert Expansion due to temperature change to stress for example on elbow? in other words I need to know the relation between temperature change and force and moments on anchors and restrains and stresses on components.

Best regards

There'll be differences from piping code to piping code, but the gist is as follows. An elbow consists of 2 elements, which are input with 3 nodes in succession. Let's say 10-20-30.

CAESAR converts this input "behind the scenes" to add nodes at the inlet side of the bend, middle of the bend, and outlet side of the bend. If you already have a node at the inlet and outlet weld points, CAESAR will throw up an error and ask you to correct the situation.

The two elements, however, are two sticks. When you provide geometrical data, CAESAR calculates the flexibility and stress intensification factors for movement of these two sticks relative to each other so as to represent a bend.

CAESAR simulates how much motion there exists based on a series of stiffness values and internal/external forces, and based on the derived motion, calculates an equivalent stress.

In the case of an elbow anchored on either end (10-20-30), the growth from 10-20 is resisted by the lateral stiffness from 20-30 and vice versa. The lateral load on 30 is equal to the axial load on 10 - this is a simple free body problem. Both are equal to the amount of load that's acting to compress node 10-20 axially, which the load is the balance between the lateral stiffness of 20-30 and the axial stiffness of 10-20, based on the change in length due to thermal expansion.

Thank you Michael do you recommend any book to read to be more aware with this?

Pipe Stress Engineering by Peng is a good starting point and describes concepts well.

Kellogg piping engineering handbook is a strong basis and explains some of the history of how and why we do things the way we do.

I will also second L.C. Peng's work, which goes into greater detail.

Of course, your studies aren't complete if you haven't cracked open the piping code(s) you will be doing work in.

Where this explanation exist on Peng Book Which chapter?

Peng isn't associated with Caesar (as far as I know) so the book doesn't go into how Caesar handles elbows specifically. It's a good resource for pipe stress theories, practices, and background.

The Caesar II User Guide (Section 4 Piping Input Reference) goes into their methodology regarding node numbering. Peng discusses general beam theory which is the basis of pipe stress analysis.

I don't think that explanation is going to be found in published literature, although it's been made in pieces between various webinars and classes.

You can prove it to yourself with a test CAESAR file with a series of anchored elbows and plot forces versus area, bending inertia, bend radius, and bend flexibility factor and back out a relationship.