Design Acceleration

It seems to me that this is a matter of calculating the forces and moments resulting from the accelerations stated and then just add everything. Just note that you have acceleration. You need mass distribution information to continue, then values will start showing up. Is this a matter of evenly distributed mass? Or is it tied to some specific point? What are the structural members in the sketch, where they are going to be positioned? What's the material? It will be designed, built, reverse engineered?

Dear Friend,

Actually this motion need to applied on the vessel during shipping to offshore. Let say total length of vessel (including skirt) is 20m vertical laying horizontally on ship, material for vessel is SA 516 Gr.70, empty weight around 20 tons. You have any example regarding this matter. Could you send to me for study purpose.

Thank you.

"It frightens me that you need to ask this question given that the consequences of getting it wrong could be major."

I agree.. I suggest you (OP) contract a specialist in this field who can take documented legal responsibility for the accuracy of the calculation in the case of an insurance claim or certification investigation. It is smart to be able to do and perform the calculations, but it is wise to cover your a$$ with a professional in the industry.

Chris

Just to add clarification re my last post.

It looks like you are carrying the barge so the stuff about tow ropes is irrelevant - though it were relevant, then huge drag forces would need to be added.

It is not entirely clear to me about what sits where, but if the "load" is above/below the roll centre of the "transporter"(in shipping I think equals centre of buoyancy) there will be an offset that will translate the rotational moment into translation of the "load". Not clear if that is already in the linear acceleration figures seemingly mentioned or not.

TrevorM,

Giving you a GA vote because what you've written seems highly logical and aimed towards solving the problem. However, I can't help but think there is something else missing that FAIZOL82 has missed. In solving a land-based structural system problem with seismic activity included, loading elements are given in terms of "ground acceleration". Forces are solved using Building Code formula and applied to the foundations and joints to adequately prepare the structure for any seismic events.

However, the barge could be considered to be on a frictionless surface and any loads applied must be taken to some "foundation", in this case I would assume the tow boat. Therefore, it seems logical that simple determination of the loads about the centroid is insufficient, "acceleration" values shown would be somehow equivalent to land seismic accelerations except contributed by linear actions of the waves instead of ground motions, and this whole problem will determine the nature of the tow configuration and tow boat requirements. Without and anchoring point any loads on the barge will make it move indefinitely in the direction of the loads.

Dear All,

Thank for reply and advice, now i'm looking for example of calculate to study purpose. anybody have it. Please send to me at faizol@mset.com.my.

Thank you.

FAIZOL82,

I would think that if you have been following this thread then you'd realize that none of us has done this before, and, therefore, none of us has any sample problem or example solution that we can provide to you. Our posts clearly point out possible directions you can take to solve the problem, but we will not solve it for you. If you are in "over your head" on this, then you should seek other outside assistance as we do not have any similar solved problems for you to copy off of. Sorry.