Davit Arm Calculations 2

[Re-Eng Rana]

Hi, I'm working through calculations for a davit arm design, from Pressure Vessel Design Manual 3rd Edition by Dennis R. Moss, to check against my calculations. The web link as follows is best for descibing it:

https://www.excelcalcs.com/calcs/search-calcs/Strength/Structural-Details/DAVIT-ARM/

Questions:
1. Has anyone gotten effective results from it?
2. Section 3.1 Bending Moment, what is the 'l' (lower case L) in M = lV, contributed from: Pressure Vessel Handbook 12th Edition by Eugene F. Megyesy?
3. Does any one have better analytical analogy for Type 1 davit arm design?
Thanks heaps.
Referencing Eng-Tips closed post: thread794-332471

 

[r6155]

Avoid calculations, try to use standard davit as per PIP VESSEL STANDARD DETAILS.

Regards

 

[oknow]

Have UG-22 Loadings been considered? What about the attachment welds? Any fillet welds been evaluated in the shear?

 

[r6155]

@ oknow
Have you the PIP VESSEL STANDARDS DETAIL?

Regards

 

[Re-Eng Rana]

You guys are gun! Thank you for your responses. I haven't had to engineer pressure vessels before and I am not familiar with the codes you're referring to, and I don't have the PIP Vessel Standards Detail. My main concern is the height of the davit that I can go to with the lightest SHS steel...hence the calcs. Welds aren't a problem. If you can please direct me closer (Section, page number, web site) to what you're both referring to in the documents you mention, that would be so awesome as I have not found anything useful yet (I'll keep working at it).

 

[oknow]

r6156..I do not have that PIP Vessel Standard but from what I viewed on a search seems to be Procedural type of document to which I am not sure who would use or how it is incorprated into ones Quality System. Just how it would support the design of the davit for ASME UG-22 Requirements. The 2019 revision to UG-44(b) requirements may also impact the davit attachments

 

[SnTMan]

Re-Eng Rana, please clarify: Davit is attached to a pressure vessel, or no? "Sand bagging"?

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Re-Eng Rana]

Hi Mike, SnTMan,
The davit isn't attached to a pressure vessel. In this case it is similar to sand bagging..it's a 1 tonne lifting frame...6m tall.

oknow and r6156, I cannot find anything useful in the documents you have suggested, sorry. But Maybe i don't have access to it all.

Thanks heaps!!

 

[r6155]

See

https://pip.org/practices

Regards

 

[Re-Eng Rana]

An update for all these champions for helping me, and for future designers, the formulas I was following, noted in my first post, are correct. The one thing I did not have correct was the strength of the steel SHS member mast. It required to be 350MPa as a minimum, not the 250MPa that I was using.
I really appreciate having others out there who gave me support. Thank you.

 

[r6155]

All thickness in PIP Davit are based on 36 ksi Yield Strength.

Also see Pressure Vessel Design Manual by Dennis R. Moss, 4TH Ed.

Regards