150 Deg Lobster bend modeling in CII

Dear all,

I have a 150 deg. lobster bend in design. CII limits the bend angle from 5 to 135 Deg.

How can I stimulate 150 deg bend in CII.

Regards,

Use multiple bends.

You have control over the allowed bend angle. By default bends can be defined between 5 and 95 degrees.
This is specified in the configuration file [CAESAR.CFG].

I had to see what a lobster bend looks like...
If yours is a reducing miter joint, I suggest you first build a collection of single cut miters and then change the ODs for the reduced sections. Here's a picture from one of the (upcoming) Piping Design Online training segments:

They are typically series of miter-cut, off-centered reducers... never concentric, but sometimes eccentric. The reducers themselves are irregular conic sections whose miter cuts are supposed to be circular. Regular cones do not produce circular cuts when cut at these angles.

To that end, it would be ideal to get an accurate model of the bend in question and measure the diameters at the miter cuts/welds. You could then model a miter bend of that diameter at each weld point.

It's worth mentioning that miter cuts needn't necessarily be at regular intervals. E.G. I've seen one comprised of 3 pieces (where Dave shows 4), but the miters were supposedly at 25° and 72°, instead of 30° and 60° as one might expect.

Thanks everyone.

The issue is we are stress analyzing one of a existing piping systems. No reference drawings available apart from a old isometric. The isometric says 150 deg lobster bend. The line is insulated at site to check what is actually existing.

I have used multiple bends as per Richard's suggestion and covered it as assumption in the report. In the complete analysis this assumption seems to be good enough, that there is sufficient flexibility on either sides of the bend and it is not close to any of the nozzles etc.

Thanks again everyone.

Thanks every one. This was very helpful.