Pressure Vessel Lug Design 1

[dannyo]

I am trying to follow the Pressure Vessel Design Manual's (by Dennis R. Moss) proceedure for the design of lug supports. I have run into a units proplem, however. The equation for the uniform load on base plate (w) has the wrong units. In the notation (nomenclature) section, (w) is stated to have units of (lb/in). The equation is
w = Q/(a*l) where (Q) is the vertical load per lug (lb), (a) is the bearing length (in), and (l) is the length of the base plate across the gussets (in). As you can see, the units per the equation are (lb/in2). Is this equation wrong? The rest of the proceedure is incorrect (units wise) as it is currently written. Could anyone please help our with this? Thanks in advance!

Best regards,

Danny

 

[murgan]

dennis moss literally sucks

use Bednar

Thanks

Murgan
murgan1@hotmail.com

 

[ksuengrng]

Dannyo,

I also use to use the book by Moss, but ran into so many mistakes, units problems, and incorrect formulas that I try to stay far away from it.

I would recommend using Henry Bednar's book or the book by Eugene Megyesy (Pressure Vessel Handbook). Both of these are excellent resources to have. Others include books by Kanti K. Mahajan, Lloyd Brownell, and Edwin Young.

I would really recommend not using the book by Moss anymore, unless they have really revamped it and ensured that the mistakes from previous printings have been eliminated.

 

[welding1]

I once remember seeing a pressure vessels lugs lift and the vessel remained on the floor. Make sure the pressure vessel material is not laminated; UT is not a bad idea. The other point to remember is if the force is applied at an angle it will be greater than if it were applied vertical and at an angle you can peel off the lifting lug. I have lots of formula for calculating the strength of welded joints which you may find useful at

http://www.gowelding.com.

Don’t forget to allow for shock lifting loads and if you are using the lug to manipulate the vessel, tailing lugs, you must appreciate the geometry of the loading as the vessel moves.

If the vessel is heavy or very thin you could distort it, it may be worthwhile doing a local load calc to WRC 107 or BS5500 on the shell.