Mitre Bend Dimensions - Calculation Formulae

[Pavan Kumar]

Hi All,

I am doing Pipe Stress Analysis that involves me to model two 36" Mitre Bends. The first 36" bend is a 45 Degree Mitre bend with one cut section and the second one is a 90 degree Mitre bend with 4 cut sections. I wanted to know if anyone can post the formulae to calculate the Mitre Bend dimensions such as Bend Radius (R), dimensions A, B, C,D and E. If you can point me to the relevant document where I can find these formulae also it would be great.

Thanks and Regards,
Pavan Kumar

 

[KevinNZ]

You decide the number of cuts and the total bend radius. Draw it up in CAD. The SIF is calculated from design code.

 

[TBP]

The Pipe Fitter's And Pipe Welder's Handbook (a small, soft cover book that you can buy on Amazon) has a chapter that includes the calculations & layout for fabricating fittings like this.

 

[saplanti]

Unless you are a competent engineer how to use mitre bending do not use it since many competent engineers still getting wrong in the details.

First you need to understand that a proper circular geometry is needed to weld onto the piping on both side. So you need a straight length with circular peace for this purpose. Other than that selecting the number of internal peaces is your choice, but if you are going to analyse the piping agains the codes you may need to stick the code images for the established stress intensification factors unless you do not know SIF for your selection.

You can cut the peaces from the straight pipe or develop and formula to make the peaces from plate in case the code allows this construction with longitudinal welding for fitting.

Everything is geometry, I guess you can manage it.