Design forces to use for Ocean Shipping of pressure vessels 2

[jwsmith88]

Does anyone know the typical forces If there are such) that should be used in the design of pressure vessel saddles for items being shipped by ocean transportation?

 

[LSThill]

jwsmith88 (Mechanical)

DENNIS MOSS PRESSURE VESSEL HAND BOOK 3RD

7 Transportation and Erection of Pressure Vessels

Procedure 7-1 Transportation of Pressure Vessels

Page 365 – 373 Table Barge Shipping Forces
Page 374 Pitch, Roll; Forces in Vessel Due to Pitch
Forces in Vessel Due to Roll
Page 375 Direction of Ship Motions

Regards
Leonard Stephen Thill

 

[LSThill]

jwsmith88 (Mechanical)

Technical Note:

Saddle Pro by Paulin Research Group

http://www.paulin.com

design of pressure vessel saddles for items being shipped by ocean transportation.

L S THILL

 

[MJCronin]

Well, I would assume that the vessel will be empty for shipping.

Furthermore,it is reasonable to assume that the loads generated by wave action cannot be more than half of gravity and that they would act on a line no higher than 45 degrees from verical. (this would be rough seas)

Input these loads into a canned program to evaluate saddles/legs on vessels and see what you get.

I am sure that there is a guideline out there somewhere that better defines this loading.

-MJC

 

[jwsmith88]

Thank you Sir!!!! Excellent instructions.

 

[LSThill]

Page 375 Direction of Ship Motions


The job of the designer is to translae the loads resulting form the movement of the ship into loads applied to the pressure vessel that is stroed either at or below decks. The ship itself will rotate about its own center of buoyancy (C.B.)dependingon the diredtin of the sea and the ship's oritatin to the direction of sea. The vessel strapped toits deckis in turm affected byh its locatin in relatin to the C.B. of the ship. For example,if the C.G. of the vesselis located near the C.B. of the ship, the forces are minimized. Thw farther apart the two are i relatin to each other, the more pronounced the effect on the vessel.

the ship's movement translate into loads on the three pricipalaxes of the vessel.Saddle and lashing must be stroung enugh to resti these external forces without exceeding some allowable stress point in the vessel. The poing of applicatin of the load is the C.G. of the vesssel. these loads addect the vessel in the same mannner as seismic forces do. In fact, the best way to think of these loads is as verticala dn horizontal seismic forces. Vetical seismic forces either add or subtract to the wiengt of the vessel. Hotizontal seismic forces are either transverse or lingitudinal.

The X,Y, and Z axis translate into and are ewuivalent ot the follwoing loading in the vessel:

X axis: horizontal transverse.
Y axis: correspouds tovertidcal losds by either adding or subtracting form the weight of the vessel
Z axis: longitudinal axis of the vessel. All A azix are longitudinal loadings

Load Cobinations for Sea Forces:

1 dead load + sway + heave + wind
2 dead load + surge + heave + wind

Stephen
Leonard Stephen Thill

 

[LSThill]

jwsmith88 (Mechanical):

American Bureau of Shipping (ABS) STEEL VESSELS 1999, PART 5 SECT.4 Vessel Intended to Carry Liquefied Gases and Chemical Cargoes in Bulk, MARINE.



L S THILL